Jump to content
  • Member Statistics

    17,586
    Total Members
    7,904
    Most Online
    23Yankee
    Newest Member
    23Yankee
    Joined

Sunday/Monday AM storm threat


free_man

Recommended Posts

Paul--mby question. How are things shaping up for the NW corner of Mass? We've seen most activity in the SW corner so far this year.

New forecast has upped the ante on pop to 70% today/90% tonight.

It's always extremely difficult pinpointing down convection to a specific location or small area but NW MA is in the threat area for severe storms; the numbers are about as good there as anywhere else as far as instability/shear is concerned.

12z NAM coming in and actually it doesn't look all too bad...although it is on the weak side with the ML lapse rates it definitely isn't showing any issues with instability or shear. Actually it developes the strongest helicity values right in western/central MA and CT...east of where the SPC has the 5% TOR risk.

Link to comment
Share on other sites

  • Replies 611
  • Created
  • Last Reply

Sterling VA AFD for me.. WOWWWWW

.NEAR TERM /THROUGH MONDAY/...

WEAK SHRTWV TROF THIS MRNG INITIATED CNVCTN IN THE BALTIMORE AREA.

THESE TSTMS CONTAINED HVY RAIN AND MODESTLY GUSTY WINDS...BUT LKLY

WERE ELEVATED. RECOVERY IS XPCD IN THE WAKE OF THIS WAVE AND AHEAD

OF THE STRONG TROF THAT WILL IMPACT THE RGN EARLY THIS AFTN.

CNVCTN OVER WV WILL CONT TO MOVE EWD THIS MRNG. WITH HEATING OF

VERY MOIST AMS OVER FCST AREA...THIS CLUSTER OF SHWRS AND TSTMS

WILL MOVE INTO INCRGLY UNSTABLE ENVIRONMENT. UPSWING IN INTENSITY

AND CVRG OF CNVCTN XPCD BY EARLY AFTN AS SFC TROF SHARPENS AND AMS

CONTS TO DESTABILIZE.

MODIFIED KIAD 12Z SOUNDING CONTAINS 3000 J/KG CAPE WITH MEAGER

INHIBITION. AS FORCING FOR ASCENT INCRS AHEAD OF APRCHG TROF AND

MID-LVL JET NEARS...CNVCTN SHUD BLOSSOM EASILY. AS DP-LYR SHEAR

INCRS...UPDRAFTS SHUD BCM INCRGLY ORGANIZED...FAVORING BOTH

CELLULAR AND LINEAR MODES. SUPERCELLS AND BOWING LINEAR STRUCTURES

CAN BE XPCD.

SGFNT SVR WIND EVENT WILL BE PSBL AS WET DOWNBURSTS COULD REACH

VELOCITIES IN EXCESS OF 80 MPH SPCLY E OF BLUE RDG MTNS. DRY LYR

ALOFT NOTED ON WATER VAPOR SATELLITE IMAGES ALSO WILL ENHANCE A

HAIL THREAT GIVEN THE POTENT UPDRAFTS XPCD.

LOW-LVL JET WILL STRENGTHEN THIS AFTN IN INTERSTATE 95 CORRIDOR

AHEAD OF APRCHG TROF AXIS. ALL MODELS INDICATE DVLPMT OF WEAK SFC

LOPRES ALONG THE LEE TROF AXIS...WHICH WILL FURTHER BROADEN THE

LOW-LVL HODOGRAPHS. WITH RESIDUAL OUTFLOW FROM MRNG CNVCTN AND

FAVORABLE LOW-LVL WIND FIELDS...ISOLD TORNADOES WILL BE PSBL IN

THE MOST INTENSE TSTMS...SPCLY IN NERN MD.

ALTHOUGH TSTMS WILL BE MOVG QUICKLY...THE MOST SGFNT RAINFALL IS

XPCD IN AREAS THAT HAVE BEEN IMPACTED BY SVRL ROUNDS OF RECENT

INTENSE TSTMS. AS A RESULT...FLASH FLOOD GUIDANCE IS LOW. FLASH

FLOOD WATCH HAS BEEN ISSUED FOR THIS AFTN AND EVE.

CDFNT WILL MOVE ACRS RGN THIS EVE AND LKLY WILL BE ACCOMPANIED BY

SHWRS AND TSTMS. SVR WX THREAT WITH THESE TSTMS MAY BE LESSER

OWING TO WORKED-OVER ATMOSPHERE FROM THIS AFTN. BUT IT CANNOT BE

SAID WITH CONFIDENCE THAT A SECOND ROUND OF SVR WX IS NOT PSBL

THIS EVE.

RAPID DECR IN PCPN XPCD BEHIND THE CDFNT...BUT CLD CVR MAY LINGER

THRU MUCH OF TNGT. LOW LVLS WILL DRY OUT AS CDFNT CROSSES...WHICH

MAY HELP MINIMA TO FALL LWR THAN THEY OTHERWISE MIGHT IN SUCH CLDY

CONDS.

Link to comment
Share on other sites

Fail or not, you have to like the wind fields tonight. Elevated CAPE should be there as well.

There'll definitely be a couple hour window for some solid winds. I'm still not all that impressed if we're looking for anything more than some isolated damaging winds, and generally run-of-the-mill gusts everywhere else. At least storms could continue to be surface based, with high dps and no cap, which will help mix down some of the strongest winds.

I think the main threat is flooding. These forecast soundings are close to moist adiabatic and unstable throughout the column.

Otherwise, I'm not as impressed with the wind threat as everyone else, and wb0 heights are too high for a good hail threat.

Link to comment
Share on other sites

There'll definitely be a couple hour window for some solid winds. I'm still not all that impressed if we're looking for anything more than some isolated damaging winds, and generally run-of-the-mill gusts everywhere else. At least storms could continue to be surface based, with high dps and no cap, which will help mix down some of the strongest winds.

I think the main threat is flooding. These forecast soundings are close to moist adiabatic and unstable throughout the column.

Otherwise, I'm not as impressed with the wind threat as everyone else, and wb0 heights are too high for a good hail threat.

Well I'm not necessarily expecting widespread winds, just the wind field aloft looks impressive.

Link to comment
Share on other sites

MCD

mcd2030.gif

I was wondering when they would put one up.

MESOSCALE DISCUSSION 2030

NWS STORM PREDICTION CENTER NORMAN OK

1054 AM CDT SUN AUG 21 2011

AREAS AFFECTED...PARTS OF NRN VA...THE DELMARVA...SRN AND ERN

PA...NJ...INTO THE LWR HUDSON VALLEY

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 211554Z - 211800Z

TRENDS ARE BEING MONITORED FOR AN INCREASING SEVERE THREAT THAT

COULD REQUIRE ONE OR MORE WATCHES DURING THE 17-19Z TIME FRAME.

BENEATH DIFLUENT UPPER FLOW DOWNSTREAM OF A VIGOROUS SHORT WAVE

TROUGH NOW TURNING EASTWARD THROUGH THE GREAT LAKES REGION...

SCATTERED THUNDERSTORM ACTIVITY IS ONGOING THROUGH MUCH OF THE

NORTHEAST. ASSOCIATED CLOUD COVER AND PRECIPITATION ARE SLOWING

BOUNDARY LAYER DESTABILIZATION IN BROAD POCKETS...COMPLICATING THE

SEVERE WEATHER POTENTIAL...WITH SOUTHWESTERLY DEEP LAYER MEAN FLOW

AND SHEAR STILL SOMEWHAT MODEST ACROSS MUCH OF THE REGION.

IT DOES APPEAR ONE AREA OF FORCING FOR ASCENT ASSOCIATED WITH A

SMALLER SCALE IMPULSE/WEAK AREA OF MID-LEVEL HEIGHT FALLS IS

BEGINNING TO SHIFT EAST NORTHEAST OF THE CENTRAL APPALACHIANS. THIS

COULD SUPPORT INCREASING STORM DEVELOPMENT WITHIN THE NEXT FEW HOURS

ACROSS NORTHERN VIRGINIA INTO PARTS OF SOUTH CENTRAL/ SOUTHEAST

PENNSYLVANIA...WHERE STRONGEST SURFACE HEATING IS OCCURRING. LATEST

RUC GUIDANCE SUGGESTS INHIBITION FOR MOIST BOUNDARY LAYER PARCELS

CHARACTERIZED BY 70F+ SURFACE DEW POINTS IS DIMINISHING...AND MIXED

LAYER CAPE COULD EXCEED 2000 J/KG TOWARD THE 18-20Z.

THEREAFTER...THE SEVERE WEATHER POTENTIAL...INCLUDING THE RISK FOR

ISOLATED SUPERCELLS AND ORGANIZED STORM CLUSTERS...APPEARS LIKELY TO

GRADUALLY INCREASE THROUGH THE REMAINDER OF THE AFTERNOON. THIS

PROBABLY WILL INCLUDE AREAS FROM THE LEE OF THE LOWER GREAT LAKES

EASTWARD INTO NEW ENGLAND...BUT IT REMAINS UNCLEAR WHETHER THE

THREAT WILL BECOME WIDESPREAD...OR REMAIN RELATIVELY LOCALIZED

ACROSS THESE AREAS.

..KERR.. 08/21/2011

Link to comment
Share on other sites

looks like no TOR watch for wizzy based on that MCD.

I really am not sure what to make of the svr threat today. There's definitely been more sun than I expected... even from 10z this morning. Instability and shear look good but I'm still pretty hesitant to pull the trigger on a big event given some of the negatives still floating around.

Link to comment
Share on other sites

looks like no TOR watch for wizzy based on that MCD.

I really am not sure what to make of the svr threat today. There's definitely been more sun than I expected... even from 10z this morning. Instability and shear look good but I'm still pretty hesitant to pull the trigger on a big event given some of the negatives still floating around.

What are you concerned about the most as far as negatives go?

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...