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Western/Central Region Arctic Outbreak/New Year's Eve/New Year's Day/Early January Winter Storm


Srain

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The much talked about Arctic front is advancing South and West with an Omega Pacific Coast blocking regime and a cold upper trough diving S into the Sacramento and San Joaquin Valleys with its near 1060mb High pressure cell over Montana/Wyoming and the very cold upper trough out West continues to drop toward Southern California before closing off and forming a cold core upper Low near Las Vegas Tuesday morning. Very chilly temperatures across the West are expected and snow is likely in Las Vegas, just N of Phoenix into Tucson, very far S in New Mexico, and West Texas as the Arctic front spills E over the Eastern Mountain gaps of the New Mexico into the Rio Grande River High Plains. The Arctic high will settled into Western Kansas and modify to around 1045mb which gives us an idea of just how dense this Arctic air mass is. The front will clear the Texas Coast Tuesday afternoon/ evening with increasing cold air advection Tuesday night into New Year’s Eve.  A wintry mix is possible across Oklahoma into Missouri and Arkansas.

 

The challenging part of the forecast for much of Texas begins in earnest New Year’s Eve afternoon as up glide and over running moisture from the Eastern Pacific begins to saturate the upper/mid levels. The worrisome forecasting challenge is what the short term meso guidance indicates Wednesday afternoon. Light precipitation breaks out along the Rio Grande as the closed upper low begins to slowly move E over Arizona. The GFS and ECMWF are a bit drier with the surface boundary versus the aggressive NAM/WRF/SREF meso guidance that suggest a couple of 100th of an inch of light drizzle or light rain breaks out across S Central Texas spreading ENE New Year’s Eve night. Those shorter range models also suggest that surface temperatures are just below freezing along and N of the I-35 Corridor from just N of San Antonio and Austin and just W of the Dallas/Ft Worth area. The 2 meter temperature profiles for SE Texas as near 34 to 36 degrees along and N of I-10. These temperature profiles at the surface may…big emphasis on may…might be too warm 72 plus hours out via the computer guidance. The NAM and SREF are suggesting an upper air disturbance arrives ahead of the main closed core upper low generating just enough lift to saturate the surface boundary during our New Year’s Eve festivities as we ring in the New Year. This continues into New Year’s Day. The next fly in the ointment is a Coastal wave developing Thursday night and just how close to the Coast a warm front actually makes it. The current thinking is the Coastal wave and warm from may remain just offshore, but warming temperatures are depicted by the guidance as the Arctic high weakens and retreats E. It is noteworthy that the computer models often are too quick to erode the cold air at the surface once it becomes entrenched, so we will need to monitor the trends the next couple of days. The most worrisome period in New Year’s Eve and early New Year’s Day at the moment. With so many forecasting challenges to a busy Holiday period, it is prudent to keep tabs on the weather closely later today and tomorrow into Wednesday before venturing out for a night of New Year’s Eve activities. The Wintry mix is expected to expand NE across the Southern Plains into Southern Missouri and Arkansas as we near the end of the week.

 

 

 

 

 

 

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Rare Winter Storm Warning issued for the San Diego Coastal Mountains on inland and a Winter Storm Watch issued for the Mountains near Los Angeles...

 

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE SAN DIEGO CA
130 PM PST MON DEC 29 2014

...LOW ELEVATION SNOW POSSIBLE LATE TUESDAY NIGHT AND WEDNESDAY...

.A VERY COLD STORM ORIGINATING FROM CANADA WILL MOVE ACROSS
SOUTHERN CALIFORNIA LATE TUESDAY THROUGH WEDNESDAY. SNOW LEVELS
WILL FALL RAPIDLY TUESDAY EVENING AND INTO THE OVERNIGHT
HOURS...REACHING AROUND 2000 FEET AND MAY BE LOCALLY LOWER. THIS
SHOULD BRING SNOW TO THE HIGH DESERT FLOOR IN THE APPLE AND
LUCERNE VALLEY AREAS...AROUND YUCAIPA AND BEAUMONT IN THE INLAND
EMPIRE...AND NEAR ALPINE IN SAN DIEGO COUNTY. THERE WILL OF COURSE
BE SNOW IN ALL OF THE MOUNTAIN AREAS TOO. SNOW SHOWERS WILL TAPER
OFF WEDNESDAY AFTERNOON FROM NORTH TO SOUTH.

CAZ048-050-055>058-060-300600-
/O.UPG.KSGX.WS.A.0003.141231T0000Z-150101T0000Z/
/O.NEW.KSGX.WS.W.0004.141231T0000Z-150101T0000Z/
SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-
SAN DIEGO COUNTY VALLEYS-SAN BERNARDINO COUNTY MOUNTAINS-
RIVERSIDE COUNTY MOUNTAINS-SANTA ANA MOUNTAINS AND FOOTHILLS-
SAN DIEGO COUNTY MOUNTAINS-APPLE AND LUCERNE VALLEYS-
INCLUDING THE FOLLOWING LOCATIONS...BEAUMONT...YUCAIPA...
POTRERO...ANGELUS OAKS...BALDWIN LAKE...BARTON FLATS...
BIG BEAR CITY...BIG BEAR LAKE...CRESTLINE...FAWNSKIN...
FOREST FALLS...I-15 AT CAJON SUMMIT...I-15 AT 3500 FEET...
LAKE ARROWHEAD...MOUNT BALDY...MOUNTAIN HOME VILLAGE...OAK GLEN...
PHELAN...RUNNING SPRINGS...TWIN PEAKS...WRIGHTWOOD...AGUANGA...
ANZA...GARNER VALLEY...IDYLLWILD...MOUNTAIN CENTER...PINE COVE...
PINYON PINES...VISTA GRANDE...CASE SPRINGS...
ORTEGA HIGHWAY AT 2600 FEET...BOULEVARD...CAMERON...CAMPO...
CUYAMACA...DESCANSO...JULIAN...LAKE HENSHAW...MORENA VILLAGE...
MOUNT LAGUNA...OAK GROVE...PINE HILLS...PINE VALLEY...RANCHITA...
SANTA YSABEL...WARNER SPRINGS...ADELANTO...APPLE VALLEY...
EL MIRAGE...HELENDALE...HESPERIA...LUCERNE VALLEY...VICTORVILLE
130 PM PST MON DEC 29 2014

...WINTER STORM WARNING IN EFFECT FROM 4 PM TUESDAY TO 4 PM PST
WEDNESDAY ABOVE 2000 FEET...

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A WINTER
STORM WARNING ABOVE 2000 FEET FOR HEAVY SNOW AND GUSTY WINDS...WHICH
IS IN EFFECT FROM 4 PM TUESDAY TO 4 PM PST WEDNESDAY. THE WINTER
STORM WATCH IS NO LONGER IN EFFECT.

* SNOW LEVELS...FALLING FROM AROUND 4500 FEET IN THE NORTH AND
  6000 FEET IN THE SOUTH ON TUESDAY AFTERNOON...TO BETWEEN 2000
  AND 2500 FEET OVERNIGHT. LOCALLY LOWER SNOW LEVELS DOWN TO 1000
  FEET.

* SNOW ACCUMULATIONS...2 TO 7 INCHES IN THE HIGH DESERT. 6 TO 12
  INCHES IN THE SAN BERNARDINO MOUNTAINS WITH UP TO 15 INCHES IN
  THE HIGHER PEAKS. 6 TO 12 INCHES IN THE RIVERSIDE AND SAN DIEGO
  COUNTY MOUNTAINS. 1 TO 4 INCHES ABOVE 2000 FEET.

* TEMPERATURES...VERY COLD TUESDAY NIGHT AND WEDNESDAY NIGHT
  WITH...TEMPERATURES BOTTOMING OUT IN THE TEENS IN THE HIGH
  DESERT AND IN THE SINGLE DIGITS IN THE MOUNTAINS. WIND CHILL
  VALUES MAY FALL BELOW ZERO AT TIMES IN THE MOUNTAINS.

* WINDS...OVER THE HIGH DESERTS AND NORTHERN MOUNTAINS...NORTHWEST
  20 TO 30 MPH WITH GUSTS TO 50 MPH THROUGH PASSES AND OVER RIDGES
  TUESDAY EVENING...SHIFTING TO THE NORTH WEDNESDAY MORNING...WITH
  LOCAL GUSTS UP TO 60 MPH. OVER THE SOUTHERN
  MOUNTAINS...SOUTHWEST TO WEST 10 TO 20 MPH...WITH GUSTS UP TO 30
  MPH.

* VISIBILITY...REDUCED TO BELOW ONE-HALF MILE IN SNOW AND BLOWING
  SNOW.

* IMPACTS...MAJOR TRAVEL PROBLEMS POSSIBLE DUE TO SNOW AND ICE.
  TRAVEL CORRIDORS INCLUDING INTERSTATES 8...10...15...MANY STATE
  AND COUNTY HIGHWAYS WILL BE IMPACTED WITH DELAYS OR CLOSURES
  POSSIBLE.
 

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Morning briefing from Jeff:

 

Winter Storm likely over a large part of TX NYE and NYD with travel impacts.

 

Mainly cold rain for most of SE TX.

 

Arctic cold front be driven by impressive 1055mb high pressure cell over MT this morning continues to ooze its ways southward under unfavorable WSW flow aloft. Dense cold air mass damming against the higher elevations of the southern Rockies is helping to force the cold air south across west TX and it will gradually spread eastward across the rest of the state today. Temperatures today will warm slightly into the mid 50’s prior to the onset of cold air advection and then begin to fall this afternoon as the arctic air begins to filter into the region. Upstream temperatures over CO are very cold in the 1’s and this air mass will continue to surge down into WC and NW TX today.

 

NYE:

Cold arctic air mass will be in place with warm nose on WSW flow aloft above the surface cold pool. This will certainly create a thick deck of clouds allowing for very little if any warming on Wednesday. Still think the best course of action is to undercut guidance numbers by up to 5 degrees and go with near steady temperatures in the mid to upper 30’s not the upper 40’s. Strong upper level storm system over the US west coast begins its track toward TX on NYE with lift starting to increase NYE night over the top of the surface cold dome. An extensive review of forecasted surface low temperatures and dewpoints/wet bulb suggest most of SE TX will remain liquid. Forecast profiles show a strong warm nose above the arctic cold dome favoring only freezing rain if the surface temperature were to fall to freezing. Dewpoints in the upper 20’s for College Station and Huntsville late NYE night/NYD with surface temperatures of 32-35 suggest onset of light precipitation in this region (far north and west) may be enough to lower the surface temperature to freezing and result in freezing rain/drizzle. This would be a very marginal ice threat given warm ground temperatures and temperatures in the 31-33 degree range…still some bridges and overpasses NW of a line from Columbus to Brenham to Huntsville could see some ice accumulation late NYE night into NYD. Still a lot of uncertainty in this part of the forecast.  

 

Bigger problems appear along and west of I-35 northward into OK where sub freezing surface layer and higher QPF values support more significant ice accumulations. Hence A Winter Storm Watch is issued along and NW of a line from Del Rio to west of Georgetown and this watch may be extended eastward to include portions of the I-35 corridor late today or possibly an advisory. Travel impacts are likely in the Winter Storm Watch area NYE night and NYD.

 

NYD:

Cold and wet with only a very slow temperature recovery from morning lows in the mid 30’s. Coastal trough is forced off the lower TX coast due to incoming storm system from the west. Widespread lift from the coastal trough lifting northward toward the coast will result in numerous showers all day with temperatures slowly warming into the upper 30’s. Think any potential freezing rain over the far north and west counties will be ended by mid morning with temperatures warming a few degrees above freezing. Should more cold air more into the region than expected then this could linger the freezing rain threat over those NW counties longer into Thursday.

 

Friday:

More cold and wet with the upper level system approaching from the west. Coastal trough will lift toward the coast and then move toward LA with widespread rain and elevated thunderstorms likely. Does not look like surface warm front will move inland much if at all keeping much of the region in the cold sector. Expect temperatures to slowly warm into the upper 40’s under widespread rain.

 

Saturday:

Upper level system moves across the state with rain continuing early. Latest model runs have shown a little bit slower of a system and this could linger rain into Saturday afternoon with continued cool temperatures.

 

Upper level system will exit east Saturday night allowing a dry and cool air mass to filter in for next Sunday with sunny skies hopefully returning.

 

Rainfall amounts over the next 2-3 days will average 1-2 inches with isolated totals of up to 3 inches possible. Grounds are wet from recent rainfall and additional widespread rainfall as is being suggested will likely result in rises on area rivers.   

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Conditions across West, NW and W Central Texas are deteriorating rather quickly as light snow is falling in Amarillo. Lubbock is reporting a 20 vehicle accident due to light icing. Midland/Odessa is reporting light icing across their area. San Angelo is reporting icing in Sweetwater. The models were not forecasting much of any precipitation today and if they were, it was extremely insignificant.

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PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
254 PM EST TUE DEC 30 2014

VALID 00Z WED DEC 31 2014 - 00Z SAT JAN 03 2015


DAYS 1-3...

...SOUTHWESTERN U.S....

A POTENT UPPER LEVEL SHORTWAVE TROUGH IS DROPPING SOUTHWARD ALONG
THE SOUTHERN CALIFORNIA COAST AND IS EXPECTED TO CUT OFF AT 500 MB
WHILE CROSSING FROM SOUTHERN CALIFORNIA INTO ARIZONA.  WHILE THE
SYSTEM IS ORIGINALLY MOISTURE STARVED...SOME PACIFIC MOISTURE AND
ASCENT OVER THE HIGH TERRAIN WILL SEE SNOW BREAKING OUT THIS
EVENING AND OVERNIGHT AS WEAK LOW PRESSURE DEVELOPS ALONG THE
SAGGING COLD FRONT OVER SOUTHERN CALIFORNIA. SNOW LEVELS WILL FALL
DRAMATICALLY TO NEAR 1500 TO 2000 FEET OVERNIGHT...WITH SNOWFALL
IN HIGH DESERT REGIONS AND SIGNIFICANT ACCUMULATIONS POSSIBLE
ACROSS THE SAN GABRIELS AND ACROSS THE PENINSULA RANGES. FOR DAY 1
ACCUMULATIONS...USED A MULTI MODEL BLEND OF 00Z ECMWF/12Z GFS
PARALLEL/12Z NAM/09Z SREF AND EVEN 00Z UKMET GENERATE THE
FORECAST.

ON WEDNESDAY...SIGNIFICANT MOISTURE TRANSPORT EAST OF THE TROUGH
AXIS OVER ARIZONA INTO SOUTHERN UTAH WILL INCREASE THE LIKELIHOOD
OF HEAVY SNOWFALL AMOUNTS ESPECIALLY ABOVE 3500 TO 5000 FEET.  THE
12Z PARALLEL GFS AND 00Z/12Z ECMWF WERE USED FOR THE FORECAST
THOUGH THE ECMWF QPF AMOUNTS ARE OFTEN BIASED ON THE LOW END.
THEREFORE...DAY 1 TO DAY 2 SNOWFALL AMOUNTS ARE EXPECTED TO BE AT
LEAST IN THE RANGE OF 4 TO 8 INCHES ACROSS MUCH OF THE MOGOLLON
RIM AND ACROSS THE COLORADO PLATEAU IN NORTHEAST ARIZONA AND
ACROSS THE MOUNTAINS OF SOUTHERN UTAH. AS COLD AIR CONTINUES TO
SURGE SOUTHWARD ACROSS WESTERN TEXAS...LIGHT SNOW/FREEZING RAIN
AND SLEET WILL LIKELY NOT AMOUNT TO SIGNIFICANT
ACCUMULATIONS...WITH A SMALL POSSIBILITY ACROSS CENTRAL TEXAS ON
DAY 2...BUT WILL STILL RESULT IN TREACHEROUS TRAVELING CONDITIONS
ON DAYS 1, 2 AND INTO DAY 3.

ON THURSDAY/DAY 2...THE UPPER LOW APPEARS TO SPLIT INTO TWO
COMPONENTS...ONE STREAKING AND SHEARING NORTHEASTWARD TOWARD THE
CENTRAL PLAINS WHILE WEAKENING.  THE OTHER PORTION REMAINS OVER
THE SOUTHWEST AND BEGINS TO LIFT NORTHEASTWARD ON FRIDAY/DAY 3.
SIGNIFICANT SNOW REMAINS OVER A GOOD PORTION OF THE SOUTHWEST ON
DAY 2...WITH SIGNIFICANT ACCUMULATIONS BEGINNING TO TAPER OFF OVER
NW ARIZONA BUT CONTINUING ACROSS THE HIGHER ELEVATIONS OF EASTERN
ARIZONA INTO WESTERN NEW MEXICO. SIGNIFICANT ACCUMULATIONS ARE
POSSIBLE AS FAR NORTH AS THE SAN JUANS IN SOUTHWEST COLORADO WHILE
LIGHT SNOWFALL ACCUMULATIONS ARE LIKELY EVEN ACROSS HIGH
ELEVATIONS OF SOUTHERN ARIZONA INTO SOUTHERN NEW MEXICO.

BY FRIDAY/DAY 3...THERE IS QUITE A BIT OF SPREAD WITH THE LOCATION
OF THE UPPER LOW OVER THE SOUTHWEST WITH THE 12Z GFS ON THE FAST
SIDE OF THE SPREAD AND THE 12Z UKMET ON THE SLOW SIDE.  THE 12Z
ECMWF/GFS PARALLEL AND CANADIAN WERE MORE OR LESS IN LINE AND THE
SNOWFALL FORECAST WAS BASED PRIMARILY ON A BLEND BETWEEN THE ECMWF
AND THE PARALLEL GFS...ESPECIALLY OVER NEW MEXICO...WHERE A LOW TO
MODERATE PROBABILITY OF GREATER THAN 4 INCHES WAS MAINTAINED ON
DAY 3.


KOCIN

 


 

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The very cold upper trough is over the San Diego area and the much expected closed core upper low has indeed closed off over Southern California into the NW Mexico Baja area. The disturbance that was just SW of that upper trough over the Eastern Pacific yesterday is now ejecting E across Northern Mexico and will be our upper air disturbance that should bring all the wintry mischief across Texas this afternoon into tomorrow.

 

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
919 AM CST WED DEC 31 2014

.UPDATE...
Calls to county officials along the I-10 corridor have confirmed
that road conditions are becoming more treacherous. With
subfreezing temperatures anticipated throughout the day, in
addition to light freezing drizzle, the Winter Storm Warning
bumped up to begin now, as opposed to 6 PM. Additional freezing
precipitation, with potentially heavier amounts, is possible
tonight and early Thursday. Total ice accumulations may approach
1/4 inch in some areas.

Johnson
 

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URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE FORT WORTH TX
910 AM CST WED DEC 31 2014

...A WINTER STORM WARNING IS EFFECT THROUGH THURSDAY AFTERNOON
ALONG AND WEST OF A JACKSBORO...STEPHENVILLE TO GOLDTHWAITE
LINE...

...A WINTER WEATHER ADVISORY IS IN EFFECT THROUGH THURSDAY
AFTERNOON NORTH AND WEST OF A LINE FROM BONHAM TO ROCKWALL TO WACO
TO TEMPLE...

.THE WINTER STORM WARNING AREA HAS NOT BEEN CHANGED FROM THE
PREVIOUS ISSUANCE. THE WINTER WEATHER ADVISORY AREA HAS BEEN
EXPANDED TO THE EAST TO INCLUDE THE DALLAS AND WACO AREAS.
A LIGHT WINTRY MIX IS POSSIBLE DURING THE DAYTIME HOURS TODAY...
ESPECIALLY WEST OF A STEPHENVILLE TO GATESVILLE LINE. ONLY LIGHT
ACCUMULATIONS ARE EXPECTED THROUGH THIS AFTERNOON. PRECIPITATION CHANCES
WILL INCREASE TONIGHT WITH PERIODS OF LIGHT FREEZING RAIN...AND
SLEET. ICE ACCUMULATIONS UP TO ONE TENTH OF AN INCH ARE POSSIBLE
BEFORE SUNRISE THURSDAY ACROSS THE WINTER STORM WARNING AREA WITH
ONLY TRACE AMOUNTS EXPECTED ACROSS THE WINTER WEATHER ADVISORY
AREA. THE WINTRY MIX WILL TRANSITION TO MOSTLY FREEZING RAIN ON
THURSDAY. ICE ACCUMULATIONS UP TO ONE QUARTER INCH ARE POSSIBLE
ACROSS THE WARNING AREA WITH UP TO A TENTH OF AN INCH POSSIBLE IN
THE ADVISORY AREA. PRECIPITATION SHOULD TRANSITION TO ALL RAIN
THURSDAY AFTERNOON.

TXZ100-101-115-116-129-130-141-142-010000-
/O.CON.KFWD.WS.W.0003.000000T0000Z-150101T2100Z/
YOUNG-JACK-STEPHENS-PALO PINTO-EASTLAND-ERATH-COMANCHE-MILLS-
INCLUDING THE CITIES OF...GRAHAM...OLNEY...JACKSBORO...
BRECKENRIDGE...MINERAL WELLS...CISCO...EASTLAND...RANGER...
GORMAN...STEPHENVILLE...DUBLIN...COMANCHE...DE LEON...GOLDTHWAITE
910 AM CST WED DEC 31 2014

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 3 PM CST
THURSDAY...

* TIMING...TODAY THROUGH MID AFTERNOON THURSDAY WEST OF A LINE
  FROM JACKSBORO TO STEPHENVILLE TO GOLDTHWAITE.

* ICE ACCUMULATIONS...UP TO ONE QUARTER INCH OF ICE AND SLEET.

* OTHER IMPACTS...OVERPASSES...BRIDGES...AND ELEVATED SURFACES
  WILL BE THE FIRST TO ACCUMULATE. ROADS WILL BECOME SLIPPERY AS
  WELL AND TRAVEL WILL BECOME DIFFICULT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW...
SLEET...AND ICE ARE EXPECTED OR OCCURRING. THIS WILL MAKE TRAVEL
VERY HAZARDOUS OR IMPOSSIBLE.

&&

$$

TXZ119-120-134-145-158-159-010000-
/O.EXA.KFWD.WW.Y.0010.000000T0000Z-150101T2100Z/
DALLAS-ROCKWALL-ELLIS-HILL-BELL-MCLENNAN-
INCLUDING THE CITIES OF...DALLAS...ROCKWALL...WAXAHACHIE...
ENNIS...MIDLOTHIAN...GLENN HEIGHTS...HILLSBORO...KILLEEN...
TEMPLE...FORT HOOD...WACO
910 AM CST WED DEC 31 2014

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 3 PM CST THURSDAY...

THE NATIONAL WEATHER SERVICE IN FORT WORTH HAS ISSUED A WINTER
WEATHER ADVISORY FOR FREEZING RAIN AND SLEET...WHICH IS IN EFFECT
UNTIL 3 PM CST THURSDAY.

* TIMING...THIS EVENING THROUGH MID AFTERNOON THURSDAY.

* MAIN IMPACT...ACCUMULATIONS OF ICE AND SLEET BETWEEN ONE TENTH
  AND ONE QUARTER OF AN INCH

* OTHER IMPACTS...OVERPASSES...BRIDGES...AND ELEVATED SURFACES
  WILL BE THE FIRST TO ACCUMULATE. ROADS WILL BECOME SLIPPERY AS
  WELL AND TRAVEL WILL BECOME DIFFICULT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF WINTER
PRECIPITATION MAY CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR
SLIPPERY ROADS AND PLAN ON SOME TRAVEL DELAYS.

&&

$$

TXZ091>094-102>104-117-118-131>133-143-144-156-157-010000-
/O.CON.KFWD.WW.Y.0010.000000T0000Z-150101T2100Z/
MONTAGUE-COOKE-GRAYSON-FANNIN-WISE-DENTON-COLLIN-PARKER-TARRANT-
HOOD-SOMERVELL-JOHNSON-HAMILTON-BOSQUE-LAMPASAS-CORYELL-
INCLUDING THE CITIES OF...BOWIE...NOCONA...GAINESVILLE...
SHERMAN...DENISON...BONHAM...DECATUR...BRIDGEPORT...DENTON...
LEWISVILLE...FLOWER MOUND...THE COLONY...PLANO...WEATHERFORD...
BRIAR...FORT WORTH...ARLINGTON...GRANBURY...OAK TRAIL SHORES...
GLEN ROSE...CLEBURNE...BURLESON...HAMILTON...HICO...CLIFTON...
MERIDIAN...VALLEY MILLS...LAMPASAS...COPPERAS COVE...GATESVILLE
910 AM CST WED DEC 31 2014

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 3 PM CST
THURSDAY...

* TIMING...THIS EVENING THROUGH MID AFTERNOON THURSDAY.

* MAIN IMPACT...ACCUMULATIONS OF ICE AND SLEET BETWEEN ONE TENTH
  AND ONE QUARTER OF AN INCH

* OTHER IMPACTS...OVERPASSES...BRIDGES...AND ELEVATED SURFACES
  WILL BE THE FIRST TO ACCUMULATE. ROADS WILL BECOME SLIPPERY AS
  WELL AND TRAVEL WILL BECOME DIFFICULT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF WINTER
PRECIPITATION MAY CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR
SLIPPERY ROADS AND PLAN ON SOME TRAVEL DELAYS.

 

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Morning briefing from Jeff:

 

Multiple impact Winter Storm heading for Texas.

 

Cold rain expected for all of SE TX with ice likely over portions of SW, WC, and N TX this afternoon-early Friday.

 

Winter Storm Warnings for ice accumulation in effect from Del Rio to west of Fort Worth. Travel west of I-35 to the New Mexico border is strongly discouraged due to ongoing roadway icing…conditions will worsen this evening into New Year’s Day.

 

Cold arctic cold is entrenched over the state this morning with temperatures ranging from 4 at Amarillo to 32 at Dallas and 39 at Houston. Upstream temperature at Denver fell to a recorded low of -19 this morning shattering the previous 116 year old record of -11. Cold air will continue to funnel southward across TX today with temperatures showing very little recovery under a thickening cloud deck and continued cold air advection. Radar is showing echoes approaching Houston from the WSW, but surface observation show none of this is reaching the ground due to the dry sub cloud layer. Moist advection above the surface cold dome will continue as a strong storm system moves into the SW US resulting in SW upper level flow across TX. Freezing drizzle and freezing rain will continue all day across west and northwest TX resulting in significant surface travel concerns.

 

Tonight:

Coastal trough begins to sharpen along the lower TX coast in association with incoming slow moving SW US storm. Lead short wave ejects out of this system late tonight with increasing lift over the surface cold air. Expect an increase in light rain and drizzle after midnight across SE TX in association with isentropic processes and gradual saturation of the dry surface layer. Surface temperatures will remain above freezing and do not expect any freezing drizzle/rain over any portion of SE TX tonight. There is some debate on how quickly the surface layer moistens allowing drizzle to reach the ground…given the radar trends this morning will lean toward a slightly faster onset of drizzle and light rain overnight…but mainly think this will be after midnight.  

 

For areas west of I-35 onset of precipitation will fall into a cold sub-freezing layer resulting in freezing rain/drizzle. Overnight model guidance has come in with higher QPF over portions of N TX resulting in an upgrade of the winter weather products to winter storm warnings for ice accumulation. Travel to these areas is strongly discouraged after dark tonight until about noon on Thursday. Icing of roadways will make travel extremely dangerous.

 

Thursday:

Lift increases over the region with scattered showers moving northward off the western Gulf of Mexico. Surface cold dome will remain anchored in place with temperatures holding steady in the upper 30’s to near 40 for most of the day. NE surface winds will begin to increase as coastal low develops east of Brownsville in association with downstream height falls spreading over TX from the storm system to our west. Rain, clouds, and increasing winds along with cold temperatures will result in a raw first day of 2015.  

 

Friday-Saturday:

Main upper level storm moves across the area with widespread rainfall and some thunderstorms likely. Coastal low will move from near KBRO toward KLCH over this period allowing the warm sector to back toward the coast on Friday. Do not expect the warm front to penetrate inland with the exception being possibly from Galveston Bay to Beaumont late Friday. This will keep much of the area in the cold sector with temperatures held in the 40’s with widespread rainfall. With the warm front being held near the coast or offshore, will not be concerned with any severe threat for coastal or inland sections…again will need to watch the narrow corridor from Galveston Bay to Beaumont where the warm front might push inland.

 

Main impacts will be widespread and prolonged light to moderate rainfall. Rainfall amounts Thurs-Sat will average 1-2 inches with isolated amounts upwards of 3 inches. Not expecting any flooding due to the slow nature of the rainfall but overall run-off into mainstem rivers is likely due to the widespread prolonged nature of the event.

 

Latest guidance wants to slow the ejection of the upper system down some and this may result in rain chances lingering into late Saturday evening.

 

Marine:

Coastal waters will feel strong impacts from this system with warm front cutting across this area. Additionally, NE to ENE winds ahead of the lower TX coast surface low will promote tidal increase along the upper TX and SW LA coast. Expect tides to run .5-1.0 ft above normal by early Friday and could reach 1.5 ft by late Friday. Strong to severe thunderstorms will be possible over the nearshore and offshore waters Friday and Friday night as strong dynamics overspread the unstable offshore warm sector.

 

Aviation:

Poor flying conditions expected at all SE TX terminals for the next 72 hours as low clouds, fog, light rain, and reduced visibilities are all likely. All liquid at all SE TX terminals, but upstream airports at DFW, Waco, Austin, Lubbock, Midland, Amarillo, and Oklahoma City will likely see varying degrees of freezing/frozen precipitation resulting in de-icing protocol and delays. Should see I-35 terminals improve to all liquid by noon on Thursday, but not expecting much improvement at the other locations. Expect both departure and arrival delays locally and across the southern plains.   

 

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SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MIDLAND/ODESSA TX
821 AM CST WED DEC 31 2014

NMZ027>029-033-034-TXZ045>048-050>053-057>063-067>070-074-075-
080>082-258-311800-
GUADALUPE MOUNTAINS OF EDDY COUNTY-EDDY COUNTY PLAINS-
NORTHERN LEA COUNTY-CENTRAL LEA COUNTY-SOUTHERN LEA COUNTY-GAINES-
DAWSON-BORDEN-SCURRY-ANDREWS-MARTIN-HOWARD-MITCHELL-
VAN HORN AND HIGHWAY 54 CORRIDOR-
REEVES COUNTY AND UPPER TRANS PECOS-LOVING-WINKLER-ECTOR-MIDLAND-
GLASSCOCK-WARD-CRANE-UPTON-REAGAN-DAVIS/APACHE MOUNTAINS AREA-
PECOS-MARFA PLATEAU-BIG BEND AREA-TERRELL-GUADALUPE MOUNTAINS-
INCLUDING THE CITIES OF...QUEEN...ARTESIA...CARLSBAD...
CARLSBAD CAVERNS NP...TATUM...HOBBS...LOVINGTON...EUNICE...JAL...
SEMINOLE...LAMESA...GAIL...SNYDER...ANDREWS...STANTON...
BIG SPRING...COLORADO CITY...VAN HORN...PECOS...MENTONE...
RED BLUFF LAKE...KERMIT...ODESSA...MIDLAND...GARDEN CITY...
MONAHANS...CRANE...MCCAMEY...RANKIN...BIG LAKE...ALPINE...
FORT DAVIS...FORT STOCKTON...MARFA...BIG BEND NP...MARATHON...
SANDERSON...GUADALUPE MOUNTAINS NP...PINE SPRINGS
821 AM CST WED DEC 31 2014 /721 AM MST WED DEC 31 2014/

...WINTER'S ICY GRIP...

A MIX OF LIGHT BUT PERSISTENT WINTER PRECIPITATION OVER THE LAST
18 HOURS...MAINLY FROM FREEZING DRIZZLE/FOG HAS RESULTED IN WIDESPREAD
IMPACTS ACROSS THE BASIN...SOUTHEAST NEW MEXICO...AND THE TRANS
PECOS. AS OF 730 AM CST/630 AM MST THE MIXED BAG OF PRECIPITATION
HAS LESSENED SOME WITH MAINLY PATCHES OF LIGHT SNOW AND LIGHT
FREEZING DRIZZLE AND FREEZING FOG BEING REPORTED. THE LATEST
FORECAST DATA DOES INDICATE THAT THE WINTER PRECIPITATION WILL
GRADUALLY COME TO AN END BY THE AFTERNOON AND THE POTENTIAL FOR
ADDITIONAL SIGNIFICANT ICE ACCUMULATIONS IS SLOWLY DECREASING. THE
WINTER STORM WARNING WILL REMAIN IN EFFECT TODAY. TEMPERATURES WILL
NOT RISE ABOVE FREEZING TODAY IN MOST AREAS AND THUS THE ICE WILL
HAVE LITTLE CHANCE TO MELT. THE NATIONAL WEATHER SERVICE ALONG WITH
EMERGENCY MANAGEMENT OFFICIALS RECOMMEND NOT TO TRAVEL TODAY UNLESS
ABSOLUTELY NECESSARY.

WINTER WEATHER CONCERNS WILL INCREASE AGAIN TONIGHT...ESPECIALLY
ACROSS THE LOWER TRANS PECOS AND THE SOUTHERN BASIN. AS A STRONGER
DISTURBANCE TRACKS ACROSS THE AREA LATE TONIGHT WINTER PRECIPITATION
WILL BE RENEWED AND MOST LIKELY IN THE FORM OF FREEZING RAIN. THIS
COULD PROVE TO BE ESPECIALLY HAZARDOUS SOUTH A LINE FROM THE DAVIS
MOUNTAINS TO NEAR COLORADO CITY. INTERSTATE 10 IN PECOS COUNTY COULD
BECOME VERY ICY!

HERE'S A SUMMARY OF SOME OF THE GREATEST IMPACTS...

MIDLAND INTERNATIONAL AIRPORT WAS CLOSED BETWEEN 10 PM LAST NIGHT
AND 730 AM CST THIS MORNING. ONLY ONE RUNWAY IS EXPECTED TO BE OPEN.

HUNDREDS OF VEHICLE ACCIDENTS SINCE LAST NIGHT.

CLOSURE OF DAYCARES...PRE-SCHOOLS...BUSINESSES...STATE/LOCAL
GOVERNMENT OFFICES.

NM ROAD CLOSURES...62/180 FROM CARLSBAD TO TEXAS STATE LINE.
                ...HIGHWAY 82 FROM LOVINGTON TO TEXAS STATE LINE.
TX ROAD CLOSURES...US 67 BETWEEN I-10 WEST OF FT STOCKTON TO ALPINE.
                ...LOOP 250 MIDLAND.
                ...PARTS OF HIGHWAY 191 BETWEEN MIDLAND AND ODESSA.
                ...TXDOT ROADS MAP SHOW NUMEROUS ICY ROADS.
                ...JBS PARKWAY AND BUSINESS 20 OVERPASS.
                ...THERE MAY OTHER ROADS CLOSED TOO.

CALL TO ACTION...TXDOT REQUEST 100 YARDS DISTANCE SO THEY CAN WORK SAFELY.
              ...FREEZING FOG MAY REDUCE VISIBILITY MAKING DRIVING AND
                 STOPPING EVEN MORE DIFFICULT.
              ...TEMPERATURES OF 10 TO 19 AND WIND CHILLS NEAR ZERO TO 15
                 MAY RESULT IN FROST BITE ON EXPOSED SKIN IF OUTDOORS FOR
                 AN EXTENDED TIME.
              ...PROTECT PIPES AND PETS.

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
946 AM CST WED DEC 31 2014

.UPDATE...

...WINTER WEATHER ADVISORY EXPANDED EASTWARD TO INCLUDE DALLAS AND WACO...

CURRENT OBSERVED TRENDS AND UPDATED MODEL GUIDANCE CONTINUE TO
COME IN COLDER THAN PREVIOUSLY EXPECTED...SO HAVE NUDGED DAYTIME
HIGHS AND OVERNIGHT LOWS DOWN A FEW DEGREES FOR THE NEXT 24 HOURS.
THE UPPER LEVEL DISTURBANCE THAT WILL PROVIDE THE NECESSARY LIFT
FOR PRECIPITATION TONIGHT AND TOMORROW FOR NORTH AND CENTRAL TEXAS IS
CENTERED OVER SOUTHERN CALIFORNIA/WESTERN ARIZONA AS OF 9 AM.
MODEL GUIDANCE APPEARS TO BE IN GOOD AGREEMENT THAT THIS ENERGY
WILL AFFECT THE REGION AS EARLY AS TONIGHT. AS A RESULT OF THE
TEMPERATURE TRENDS AND UPPER LEVEL SUPPORT EXPECTED TO BE IN PLACE...A
LARGER AREA OF NORTH AND CENTRAL TEXAS IS EXPECTED TO RECEIVE A
MIXED BAG OF WINTER PRECIPITATION THROUGH MIDDAY TOMORROW. THIS
TEMPERATURE TREND WARRANTED THE EASTWARD EXPANSION OF THE WINTER
WEATHER ADVISORY AS WELL.
 

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URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1015 AM CST WED DEC 31 2014

...FREEZING RAIN AND DRIZZLE EXPECTED TODAY THROUGH THE MORNING
OF NEW YEARS DAY...

.A SHALLOW...COLD...ARCTIC AIR-MASS HAS SETTLED OVER SOUTH
CENTRAL TEXAS TODAY...AND WILL REMAIN IN PLACE THROUGH NEW YEARS
DAY. AREAS OF FREEZING RAIN AND FREEZING DRIZZLE ARE DEVELOPING
ACROSS THE SOUTHERN EDWARDS PLATEAU AND THE WESTERN HILL COUNTRY
EARLY THIS MORNING...AND ARE EXPECTED TO CONTINUE FOR MUCH OF
THIS NEW YEARS EVE AND INTO THE LATE MORNING HOURS OF NEW YEARS
DAY. TEMPERATURES MAY ONLY BRIEFLY CLIMB ABOVE FREEZING LATE
TODAY BEFORE QUICKLY FALLING BACK BELOW FREEZING EARLY THIS
EVENING. THERE IS A GOOD CHANCE THAT SIGNIFICANT ICE
ACCUMULATIONS WILL DEVELOP TODAY INTO THIS EVENING...ESPECIALLY
ALONG AND NORTH OF A COMSTOCK TO BOERNE TO BURNET LINE. MOST ICE
ACCUMULATIONS SHOULD BE LESS THAN 1/10 INCH...BUT A AREAS OF
SLEET MIXED IN WITH THE RAIN COULD PRODUCE LOCALLY HIGHER ICE
ACCUMULATIONS OF AROUND 1/4 INCH. WITH STEEP ROAD INCLINES FOUND
OVER MUCH OF THE EDWARDS PLATEAU AND HILL COUNTRY...EVEN A
FREEZING RAINFALL AMOUNT OF ONE HUNDREDTH OF AN INCH COULD
PRODUCE EXTREMELY HAZARDOUS TRAVEL CONDITIONS.

TXZ171-172-183>190-010015-
/O.CON.KEWX.WS.W.0003.000000T0000Z-150101T1800Z/
LLANO-BURNET-VAL VERDE-EDWARDS-REAL-KERR-BANDERA-GILLESPIE-
KENDALL-BLANCO-
INCLUDING THE CITIES OF...LLANO...BURNET...DEL RIO...
ROCKSPRINGS...LEAKEY...KERRVILLE...BANDERA...FREDERICKSBURG...
BOERNE...BLANCO
1015 AM CST WED DEC 31 2014

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON CST
THURSDAY...

* TIMING...TODAY THROUGH NOON THURSDAY (NEW YEARS DAY).

* MAIN IMPACT...FREEZING RAIN MAY ACCUMULATE ON MANY ELEVATED
  SURFACES AND ROADWAYS...ESPECIALLY BRIDGES AND OVERPASSES
  ACROSS THE HILL COUNTRY.

* ICE ACCUMULATIONS WILL AVERAGE A TRACE TO ONE-TENTH OF AN
  INCH. HOWEVER...THERE MAY BE A BAND OF SLIGHTLY HIGHER
  ACCUMULATIONS TO ONE-QUARTER INCH ACROSS THE NORTHWESTERN HILL
  COUNTRY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS ACCUMULATIONS OF SNOW...SLEET...
FREEZING RAIN OR FREEZING DRIZZLE ARE EXPECTED OR OCCURRING. THIS
WILL CAUSE CONSIDERABLE TRAVEL PROBLEMS AND MAY POSE A THREAT TO
LIFE AND PROPERTY.

&&

$$

TXZ173-191-192-202>206-010015-
/O.NEW.KEWX.WW.Y.0010.150101T0600Z-150101T1800Z/
WILLIAMSON-HAYS-TRAVIS-KINNEY-UVALDE-MEDINA-BEXAR-COMAL-
INCLUDING THE CITIES OF...GEORGETOWN...SAN MARCOS...AUSTIN...
BRACKETTVILLE...UVALDE...HONDO...SAN ANTONIO...NEW BRAUNFELS
1015 AM CST WED DEC 31 2014

...WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO
NOON CST THURSDAY...

THE NATIONAL WEATHER SERVICE IN AUSTIN/SAN ANTONIO HAS ISSUED A
WINTER WEATHER ADVISORY FOR AREAS WEST OF THE I35
CORRIDOR IN CLOSE PROXIMITY TO THE EDWARDS
PLATEAU...SPECIFICALLY ALONG AND NORTHWEST OF A LINE FROM
BRACKETVILLE...TO LAGUNA...TO HELOTES...TO WIMBERLEY...TO LAGO
VISTA...TO LIBERTY HILL. THE ADVISORY WILL BE IN EFFECT FROM
MIDNIGHT TONIGHT TO NOON CST THURSDAY.

* TIMING...MIDNIGHT TONIGHT THROUGH TOMORROW MORNING. (NEW YEARS DAY)

* MAIN IMPACT...PATCHY SLICK SPOTS ON AREA ROADWAYS DUE TO MINOR
  SLEET AND ICE ACCUMULATIONS SPECIFICALLY IN CLOSE PROXIMITY TO
  THE EDWARDS PLATEAU.

* WHILE ACCUMULATIONS ARE EXPECTED TO BE MINOR...A VERY LIGHT
  GLAZING OF ICE ON EXPOSED SURFACES...SIDEWALKS...AND LIGHTLY
  TRAVELLED ROADWAYS MAY RESULT IN POTENTIALLY HAZARDOUS DRIVING
  CONDITIONS. THIS AREA OF CONCERN IS NOT EXPECTED TO IMPACT METRO
  AREAS OF SAN ANTONIO OR AUSTIN BUT COULD POTENTIALLY IMPACT
  TRAVELLERS COMING FROM THOSE METRO AREAS AND TRAVELLING TOWARDS
  NORTHERN AND WESTERN RURAL LOCATIONS IN THOSE COUNTIES.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SLEET OR FREEZING
RAIN WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR SLIPPERY
ROADS AND LIMITED VISIBILITIES...AND USE CAUTION WHILE DRIVING.

 

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That's quite impressive considering temps was expected to be above freezing and no wintry percip. for the area!

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1015 AM CST WED DEC 31 2014

...FREEZING RAIN AND DRIZZLE EXPECTED TODAY THROUGH THE MORNING
OF NEW YEARS DAY...

.A SHALLOW...COLD...ARCTIC AIR-MASS HAS SETTLED OVER SOUTH
CENTRAL TEXAS TODAY...AND WILL REMAIN IN PLACE THROUGH NEW YEARS
DAY. AREAS OF FREEZING RAIN AND FREEZING DRIZZLE ARE DEVELOPING
ACROSS THE SOUTHERN EDWARDS PLATEAU AND THE WESTERN HILL COUNTRY
EARLY THIS MORNING...AND ARE EXPECTED TO CONTINUE FOR MUCH OF
THIS NEW YEARS EVE AND INTO THE LATE MORNING HOURS OF NEW YEARS
DAY. TEMPERATURES MAY ONLY BRIEFLY CLIMB ABOVE FREEZING LATE
TODAY BEFORE QUICKLY FALLING BACK BELOW FREEZING EARLY THIS
EVENING. THERE IS A GOOD CHANCE THAT SIGNIFICANT ICE
ACCUMULATIONS WILL DEVELOP TODAY INTO THIS EVENING...ESPECIALLY
ALONG AND NORTH OF A COMSTOCK TO BOERNE TO BURNET LINE. MOST ICE
ACCUMULATIONS SHOULD BE LESS THAN 1/10 INCH...BUT A AREAS OF
SLEET MIXED IN WITH THE RAIN COULD PRODUCE LOCALLY HIGHER ICE
ACCUMULATIONS OF AROUND 1/4 INCH. WITH STEEP ROAD INCLINES FOUND
OVER MUCH OF THE EDWARDS PLATEAU AND HILL COUNTRY...EVEN A
FREEZING RAINFALL AMOUNT OF ONE HUNDREDTH OF AN INCH COULD
PRODUCE EXTREMELY HAZARDOUS TRAVEL CONDITIONS.

TXZ171-172-183>190-010015-
/O.CON.KEWX.WS.W.0003.000000T0000Z-150101T1800Z/
LLANO-BURNET-VAL VERDE-EDWARDS-REAL-KERR-BANDERA-GILLESPIE-
KENDALL-BLANCO-
INCLUDING THE CITIES OF...LLANO...BURNET...DEL RIO...
ROCKSPRINGS...LEAKEY...KERRVILLE...BANDERA...FREDERICKSBURG...
BOERNE...BLANCO
1015 AM CST WED DEC 31 2014

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON CST
THURSDAY...

* TIMING...TODAY THROUGH NOON THURSDAY (NEW YEARS DAY).

* MAIN IMPACT...FREEZING RAIN MAY ACCUMULATE ON MANY ELEVATED
  SURFACES AND ROADWAYS...ESPECIALLY BRIDGES AND OVERPASSES
  ACROSS THE HILL COUNTRY.

* ICE ACCUMULATIONS WILL AVERAGE A TRACE TO ONE-TENTH OF AN
  INCH. HOWEVER...THERE MAY BE A BAND OF SLIGHTLY HIGHER
  ACCUMULATIONS TO ONE-QUARTER INCH ACROSS THE NORTHWESTERN HILL
  COUNTRY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS ACCUMULATIONS OF SNOW...SLEET...
FREEZING RAIN OR FREEZING DRIZZLE ARE EXPECTED OR OCCURRING. THIS
WILL CAUSE CONSIDERABLE TRAVEL PROBLEMS AND MAY POSE A THREAT TO
LIFE AND PROPERTY.

&&

$$

TXZ173-191-192-202>206-010015-
/O.NEW.KEWX.WW.Y.0010.150101T0600Z-150101T1800Z/
WILLIAMSON-HAYS-TRAVIS-KINNEY-UVALDE-MEDINA-BEXAR-COMAL-
INCLUDING THE CITIES OF...GEORGETOWN...SAN MARCOS...AUSTIN...
BRACKETTVILLE...UVALDE...HONDO...SAN ANTONIO...NEW BRAUNFELS
1015 AM CST WED DEC 31 2014

...WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO
NOON CST THURSDAY...

THE NATIONAL WEATHER SERVICE IN AUSTIN/SAN ANTONIO HAS ISSUED A
WINTER WEATHER ADVISORY FOR AREAS WEST OF THE I35
CORRIDOR IN CLOSE PROXIMITY TO THE EDWARDS
PLATEAU...SPECIFICALLY ALONG AND NORTHWEST OF A LINE FROM
BRACKETVILLE...TO LAGUNA...TO HELOTES...TO WIMBERLEY...TO LAGO
VISTA...TO LIBERTY HILL. THE ADVISORY WILL BE IN EFFECT FROM
MIDNIGHT TONIGHT TO NOON CST THURSDAY.

* TIMING...MIDNIGHT TONIGHT THROUGH TOMORROW MORNING. (NEW YEARS DAY)

* MAIN IMPACT...PATCHY SLICK SPOTS ON AREA ROADWAYS DUE TO MINOR
  SLEET AND ICE ACCUMULATIONS SPECIFICALLY IN CLOSE PROXIMITY TO
  THE EDWARDS PLATEAU.

* WHILE ACCUMULATIONS ARE EXPECTED TO BE MINOR...A VERY LIGHT
  GLAZING OF ICE ON EXPOSED SURFACES...SIDEWALKS...AND LIGHTLY
  TRAVELLED ROADWAYS MAY RESULT IN POTENTIALLY HAZARDOUS DRIVING
  CONDITIONS. THIS AREA OF CONCERN IS NOT EXPECTED TO IMPACT METRO
  AREAS OF SAN ANTONIO OR AUSTIN BUT COULD POTENTIALLY IMPACT
  TRAVELLERS COMING FROM THOSE METRO AREAS AND TRAVELLING TOWARDS
  NORTHERN AND WESTERN RURAL LOCATIONS IN THOSE COUNTIES.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SLEET OR FREEZING
RAIN WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR SLIPPERY
ROADS AND LIMITED VISIBILITIES...AND USE CAUTION WHILE DRIVING.

 

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Not really, while model guidance has been above freezing for the most part, forecasters have been discussing the potential for winter precipitation over a good chunk of Texas for over a week now. Unlike model guidance, human forecasters can look at known biases with forecast tools and make up for some of the areas that models have a hard time with, such as cold air damming. Many of these things have been discussed at length in the forum recently, and that's what separates those who merely regurgitate model data and those who are true forecasters.

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MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
145 PM EST WED DEC 31 2014

VALID DEC 31/1200 UTC THRU JAN 04/0000 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...

12Z MODEL EVALUATION ALONG WITH FINAL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 12Z
NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS.


ANOMALOUS CLOSED LOW INITIALLY OVER THE DESERT SOUTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z GFS-PARALLEL/00Z ECMWF/12Z ECMWF
CONFIDENCE: BELOW AVERAGE

MODEL TRENDS OVER THE PAST FEW DAYS HAVE SHOWN TWO MAIN VORTICITY
MAXIMA TIED TO THE CLOSED LOW CURRENTLY OVER THE
SOUTHWEST...VERSUS HOLDING TOGETHER AS ONE ENTITY. ONE VORTICITY
MAX IS FORECAST TO EJECT OUT FROM THE CLOSED LOW INTO THE CNTRL
PLAINS THU NIGHT AND WEAKEN EWD INTO CONFLUENT MID-LEVEL FLOW.
THERE SHOULD BE A POTENT SPEED MAX TIED TO THIS FEATURE...BUT THE
12Z GFS IS MUCH WEAKER THAN THE CONSENSUS HERE. THE 00Z ECMWF IS
STRONGER/FASTER BUT NOW THE 12Z ECMWF IS CLOSE TO THE TIMING OF
THE 12Z NAM AND ENSEMBLE MEANS BUT NOT QUITE AS STRONG AS THE NAM.
BASICALLY...THE 12Z ECMWF SEEMS TO SHOW A GOOD COMPROMISE AMONG
THE LATEST MODELS WITH THE VORT MAX EJECTING EWD ACROSS THE PLAINS
AND MIDWEST...WHILE THE 00Z UKMET/CMC ARE SLOWER.

NEXT IS THE REMNANT CLOSED LOW ACROSS THE SOUTHWEST...IN WHICH THE
12Z UKMET IS MUCH SLOWER TO MOVE EAST THAN THE CURRENT MODEL
CONSENSUS...THOUGH QUICKER THAN THE 00Z UKMET...AND THE UKMET
REMAINS ON THE SLOW EDGE OF THE LATEST ENSEMBLE SPREAD. THE 12Z
ECMWF TRENDED SLIGHTLY SLOWER THAN ITS 00Z RUN AND 12Z GFS
PARALLEL...WITH THE 12Z GFS PARALLEL SLIGHTLY DEEPER THAN THE 12Z
GFS. A BLEND OF THE 12Z/00Z ECMWF APPEARS TO FORM A REASONABLE
COMPROMISE WITH THE UPPER LOW SLIDING EAST FROM THE SOUTHWESTERN
CONUS...ALONG WITH THE 12Z GFS PARALLEL. THE 12Z NAM...DOES NOT
APPEAR TO BE A BAD CHOICE EITHER...ALTHOUGH IT IS MORE AGGRESSIVE
IN THE LOWER LEVELS WITH RETURN FLOW INTO THE SOUTH. DUE TO THE
COMPLICATED INTERACTION OF MANY VARIABLES WITH THIS SYSTEM...AND
POORER THAN USUAL RUN TO RUN CONTINUITY...CONFIDENCE IS BELOW
AVERAGE.

 

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