donsutherland1 Posted September 6, 2011 Share Posted September 6, 2011 First recon pass was SW/NE... Pressure much higher than the NHC 11AM estimate, sitting at 963mb. Max FL wind of 114kts in the NE quad. URNT12 KNHC 061725 VORTEX DATA MESSAGE AL122011 A. 06/16:55:00Z B. 27 deg 10 min N 066 deg 14 min W C. 700 mb 2768 m D. 66 kt E. 223 deg 36 nm F. 313 deg 85 kt G. 223 deg 40 nm H. 963 mb I. 12 C / 3047 m J. 16 C / 3045 m K. 13 C / NA L. NA M. NA N. 12345 / 7 O. 0.02 / 1 nm P. AF304 0112A KATIA OB 04 MAX FL WIND 85 KT SW QUAD 16:43:30Z MAX OUTBOUND FL WIND 114 KT NE QUAD 17:11:00Z MAX FL TEMP 17 C 220 / 6 NM FROM FL CNTR Both the pressure and maximum sustained winds seem to lie between some of the satellite guidance. This is probably a storm that is still weakening a little on account of its eyewall replacement cycle and a 100-knot hurricane seems reasonable. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted September 6, 2011 Share Posted September 6, 2011 You and Josh are talking about two (sort-of) different things. The TC reanalyses (Chris Landsea, where they go back and reanalyze TCs specifically) use knots for the reasons cited by Josh. Most of the atmospheric reanalyses (NARR, ERA, NCEP/NCAR, MERRA, CFSR) that go back and do full atmosphere analyses use SI units (i.e. m/s) for their fields. Ah, OK. Thanks for clearing that up! I'm not even aware of the atmospheric reanalysis he must have been talking about. Since we're in a tropical-cyclone thread talking about tropical-cyclone literature, I assumed we were all talking about tropical-cyclone reanalysis. Meters per second pisses me off and I quit reading any article that uses it, which has really cut down on my scientific reading burden. I think most meteorologists are fine with using knots and it's easier to communicate that way. I wonder how many scientists read those articles and know right away what 50 m/s means without having to break out a converter? Meters per second (and hectopascals) are pretentious bull****. Glad you said it. Cory always tells it like it is. Link to comment Share on other sites More sharing options...
Ed Lizard Posted September 6, 2011 Share Posted September 6, 2011 I repeat, double meters per second and you have knots. Not precise, but close enough for government work. 1m/s is 1.944 knots. Nobody should ever complain about meter/second again. I'm the first one to believe the System Internationale is a plot as nefarious as soccer in America or fluoridation (joke), but for engineering calculations, SI removes a lot of conversion factors, and for wind speed, it is intuitive based on the 1 to 2 rule of thumb. You can sort of see where the eye is... Link to comment Share on other sites More sharing options...
Down The Rabbit Hole Posted September 6, 2011 Share Posted September 6, 2011 To approximate m/s from kt, you can approximately halve the original value in kts, round, and add 1 up to 100 kts, 2 up to 180 kts, 3 up to 240 kts, etc. To go the other direction, start by subtracting the appropriate number (1 up to 50 kts, 2 up to 90 kts, 3 up to 120 kts) and then double. 100 kts ~ 51 m/s 125 kts ~ 64 m/s 165 kts ~ 85 m/s To approximate m/s from mph, you can also utilize a halving trick. Halve the mph number, round, then subtract a number based on the windspeed, that number increasing every 18 mph. Winds up to 24 mph, subtract 1, 25-42 mph, subtract 2, 43-60 mph, subtract 3, 61-78 mph, subtract 4, 79-96 mph, subtract 5, 97-114 mph, subtract 6, 115-132 mph, subtract 7, 133-150 mph, subtract 8, 151-168 mph, subtract 9, etc In the other direction, you'd start by rounding to the nearest m/s, adding a number based on range of speed, then doubling. Winds up to around 11 m/s, add 1, then increase every 9 m/s - from 12-20 m/s, add 2, from 21-29 m/s, add 3, from 30-38 m/s, add 4, from 39-47 m/s, add 5, from 48-56 m/s, add 6, from 57-65 m/s, add 7, from 66-74 m/s, add 8, and from 75-83 m/s, add 9 etc. What's especially nice about this method is that you can roughly figure out what number to add or subtract based on the Saffir-Simpson category. While not perfect, you can get away with adding/subtracting 5 from Category 1 storms, 6 from Category 2 storms, 7 from Category 3 storms, 8 from Category 4 storms, and 9 from most Category 5 storms, and come close to the actual number, +/- 1 or so. 100 mph ~ 45 m/s 115 mph ~ 51 m/s 165 mph ~ 74 m/s Link to comment Share on other sites More sharing options...
jpeters3 Posted September 7, 2011 Share Posted September 7, 2011 Meters per second pisses me off and I quit reading any article that uses it, which has really cut down on my scientific reading burden. I think most meteorologists are fine with using knots and it's easier to communicate that way. I wonder how many scientists read those articles and know right away what 50 m/s means without having to break out a converter? Meters per second (and hectopascals) are pretentious bull****. m/s are a basic SI unit, and they are used because it is easy to make calculations with them. There is nothing wrong with standardization within a scientific field, especially when it makes it easy for those who frequently have to make calculations (such as conversions to energy and pressure). It's not that hard to convert, and i don't understand why it irritates you so much. Your loss if you quit every article that uses m/s. As for hPa vs mb, who cares which one is used. They both mean the same thing! I know when I was an undergraduate and was assigned problems to solve, it was a pain in the ass to get quantities in kts. Link to comment Share on other sites More sharing options...
ArtRosen Posted September 7, 2011 Share Posted September 7, 2011 000 WTNT32 KNHC 070236 TCPAT2 BULLETIN HURRICANE KATIA ADVISORY NUMBER 36 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011 1100 PM AST TUE SEP 06 2011 ...KATIA EXPECTED TO PASS BETWEEN BERMUDA AND THE EAST COAST OF THE UNITED STATES OVER THE NEXT DAY OR TWO... SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...28.1N 67.2W ABOUT 325 MI...520 KM SSW OF BERMUDA MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H PRESENT MOVEMENT...NW OR 315 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...963 MB...28.44 INCHES WATCHES AND WARNINGS -------------------- CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY... NONE. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WATCH IS IN EFFECT FOR... * BERMUDA A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA...IN THIS CASE WITHIN 24 TO 48 HOURS. FOR ADDITIONAL STORM INFORMATION...PLEASE MONITOR PRODUCTS ISSUED BY THE BERMUDA WEATHER SERVICE. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ AT 1100 PM AST...0300 UTC...THE CENTER OF HURRICANE KATIA WAS LOCATED NEAR LATITUDE 28.1 NORTH...LONGITUDE 67.2 WEST. KATIA IS MOVING TOWARD THE NORTHWEST NEAR 9 MPH...15 KM/H...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE THROUGH WEDNESDAY...FOLLOWED BY A TURN TOWARD THE NORTH-NORTHWEST AND NORTH WEDNESDAY NIGHT AND THURSDAY. ON THE FORECAST TRACK...THE CORE OF KATIA IS EXPECTED TO MOVE BETWEEN THE EAST COAST OF THE UNITED STATES AND BERMUDA ON WEDNESDAY AND THURSDAY. MAXIMUM SUSTAINED WINDS REMAIN NEAR 105 MPH...165 KM/H...WITH HIGHER GUSTS. KATIA IS A CATEGORY TWO HURRICANE ON THE SAFFIR-SIMPSON HURRICANE WIND SCALE. GRADUAL WEAKENING IS FORECAST DURING THE NEXT COUPLE OF DAYS. HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 80 MILES...130 KM...FROM THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 205 MILES...335 KM. ESTIMATED MINIMUM CENTRAL PRESSURE IS 963 MB...28.44 INCHES. HAZARDS AFFECTING LAND ---------------------- SURF...LARGE SWELLS GENERATED BY KATIA WILL CONTINUE TO AFFECT MOST OF THE EAST COAST OF THE UNITED STATES...BERMUDA...THE GREATER ANTILLES...AND EAST-FACING BEACHES OF THE BAHAMAS DURING THE NEXT FEW DAYS. THESE SWELLS ARE LIKELY TO CAUSE LIFE-THREATENING SURF AND RIP CURRENT CONDITIONS. PLEASE CONSULT PRODUCTS FROM YOUR LOCAL WEATHER SERVICE OFFICE FOR ADDITIONAL INFORMATION. WIND...TROPICAL-STORM-FORCE WINDS...ESPECIALLY IN GUSTS...ARE POSSIBLE ON BERMUDA THROUGH THURSDAY. RAINFALL...KATIA IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 1 TO 2 INCHES ACROSS BERMUDA. NEXT ADVISORY ------------- NEXT INTERMEDIATE ADVISORY...200 AM AST. NEXT COMPLETE ADVISORY...500 AM AST. $$ FORECASTER CANGIALOSI/BRENNAN Link to comment Share on other sites More sharing options...
SACRUS Posted September 7, 2011 Share Posted September 7, 2011 Pacific like surfing the next few days Link to comment Share on other sites More sharing options...
Ed Lizard Posted September 7, 2011 Share Posted September 7, 2011 The forecasters in Europe will need to watch for Katia's exact track as she undergoes a powerful ET over the North Atlantic. A slightly further south track would bring the core of her strongest winds further south.It's always a bit of a waiting game as forecast tracks can vary while storms are still off the US East Coast.It should be interesting to track. Impressive... Link to comment Share on other sites More sharing options...
Ed Lizard Posted September 7, 2011 Share Posted September 7, 2011 NHC forecast is a post-tropical storm of hurricane force passing North, but I think the odds are decent. Link to comment Share on other sites More sharing options...
donsutherland1 Posted September 8, 2011 Share Posted September 8, 2011 At 8 pm, Hurricane Katia was centered at 30.2N 69.9W. Katia is nearing its maximum point west. Later tonight or tomorrow, Katia should be tracking northward and then turning gradually east of north. As Katia approaches 37.5N-40.0N, it should turn more dramatically to the east. Afterward, it could race across the Atlantic passing near or just to the north of the British Isles in about 4-6 days. At this point in time, I have no further changes in my estimated track. Estimated Track: 30.0N 70.0W; Actual: 30.0N 69.8W; Error: 12 miles—43.0 hours in advance 35.0N 69.6W 40.0N 63.5W Once Katia crosses 40N, I'll post the verification numbers for my track estimates. Link to comment Share on other sites More sharing options...
tmagan Posted September 8, 2011 Share Posted September 8, 2011 Katia almost has an appearance now of a decaying western Pacific typhoon. Link to comment Share on other sites More sharing options...
NorEaster27 Posted September 8, 2011 Share Posted September 8, 2011 Kati can't still be a hurricane, it looks much worse than Irene did at this latitude. Link to comment Share on other sites More sharing options...
dan88 Posted September 8, 2011 Share Posted September 8, 2011 Kati can't still be a hurricane, it looks much worse than Irene did at this latitude. The 5am advisory was buoy confirmed intensity, with 76kt sustained winds at the buoy Link to comment Share on other sites More sharing options...
weathercheck Posted September 8, 2011 Share Posted September 8, 2011 Interest moves from landfall in the US to potential landfall of a large extratropical hurricane towards the British Isles. Could prove interesting. Katia is still at 90mph hurricane as of 11am CDT HURRICANE KATIA DISCUSSION NUMBER 42 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011 1100 AM AST THU SEP 08 2011 THE CLOUD PATTERN ASSOCIATED WITH KATIA HAS NOT CHANGED MUCH IN THE PAST SEVERAL HOURS SINCE IT PASSED VERY CLOSE TO A NOAA BUOY. MOST OF THE CONVECTION REMAINS NORTH AND EAST OF THE CENTER...CONSISTENT WITH SOME WESTERLY SHEAR AFFECTING THE STORM. THE CURRENT INTENSITY IS HELD AT 80 KT BASED ON THE PRIOR BUOY OBSERVATION AND CONTINUITY OF THE CLOUD PATTERN...WITH MINIMUM CENTRAL PRESSURE ALSO HELD AT 970 MB. KATIA CONTINUES TO MOVE NORTHWARD...SLIGHTLY FASTER AT 360/15...AND RELIABLE NUMERICAL GUIDANCE SUGGESTS THAT KATIA WILL GRADUALLY TURN NORTHEASTWARD AND CONTINUE TO ACCELERATE OVER THE NORTH ATLANTIC OVER THE NEXT DAY OR SO. THERE IS VERY LITTLE CHANGE TO THE TRACK FORECAST...WHICH IS CLOSE TO THE MULTI-MODEL CONSENSUS. THE FORECAST TAKES THE REMNANTS OF KATIA NORTH OF THE BRITISH ISLES IN ABOUT FOUR DAYS. THE GLOBAL MODELS INDICATE THAT KATIA WILL REMAIN A POWERFUL CYCLONE EVEN AS IT INTERACTS WITH A MID-TROPOSPHERIC TROUGH AND ASSOCIATED STRONG WESTERLIES. THE GFS INDICATES THAT EXTRATROPICAL TRANSITION COULD OCCUR A LITTLE SOONER THAN SHOWN BELOW. FORECAST POSITIONS AND MAX WINDS INIT 08/1500Z 33.6N 70.1W 80 KT 90 MPH 12H 09/0000Z 35.6N 69.4W 80 KT 90 MPH 24H 09/1200Z 38.3N 66.8W 80 KT 90 MPH 36H 10/0000Z 40.7N 61.8W 75 KT 85 MPH 48H 10/1200Z 43.2N 53.0W 70 KT 80 MPH 72H 11/1200Z 50.0N 31.0W 65 KT 75 MPH...POST-TROP/EXTRATROP 96H 12/1200Z 59.0N 9.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 120H 13/1200Z 62.0N 2.0W 50 KT 60 MPH...POST-TROP/EXTRATROP Link to comment Share on other sites More sharing options...
phlwx Posted September 9, 2011 Share Posted September 9, 2011 http://www.nhc.noaa.gov/text/refresh/MIATCDAT2+shtml/090901.shtml Avila disco machine FTW: NO 96-HOUR POINT IS BEING GIVEN BECAUSE FORECAST POINTS IN THE EASTERN HEMISPHERE BREAK A LOT OF SOFTWARE. Link to comment Share on other sites More sharing options...
OSUmetstud Posted September 9, 2011 Author Share Posted September 9, 2011 Katia looks better than it's looked in some time. Link to comment Share on other sites More sharing options...
phil882 Posted September 9, 2011 Share Posted September 9, 2011 Katia looks better than it's looked in some time. No kidding the last couple of buoys it's gone by have suggested it's strengthening too. Link to comment Share on other sites More sharing options...
donsutherland1 Posted September 9, 2011 Share Posted September 9, 2011 Very interesting tidbit from NHC's 9/9 5 am and 11 am discussions: NO 96-HOUR FORECAST POINT HAS BEEN PROVIDED DUE TO COMPUTATIONAL ISSUES WHEN SYSTEMS MOVE EAST OF ZERO DEGREES LONGITUDE. Perhaps the 9/8 5 pm and 11 pm discussions that called for Katia to be "absorbed" used that language to finesse the apparent computational issue? Link to comment Share on other sites More sharing options...
donsutherland1 Posted September 9, 2011 Share Posted September 9, 2011 With respect to the "computational issue," it apparently has to do with the software the NHC uses. The 9/9 5 pm discussion states, "NO 96-HOUR FORECAST POINT HAS BEEN PROVIDED DUE TO SOFTWARE ISSUES WHEN SYSTEMS MOVE EAST OF ZERO DEGREES LONGITUDE." Link to comment Share on other sites More sharing options...
donsutherland1 Posted September 9, 2011 Share Posted September 9, 2011 Verification: Track Estimates: From September 2, 2011: 9:30 am 17.5N 52.8W; Actual: 17.5N 52.4W; Error: 26 miles—1.0 hour in advance 20.0N 58.6W; Actual: 20.0N 57.0W; Error: 13 miles—33.0 hours in advance 25.0N 63.9W; Actual: 25.0N 63.7W; Error: 13 miles—77.5 hours in advance 30.0N 72.0W; Actual: 30.0N 69.8W; Error: 132 miles—129.5 hours in advance 35.0N 69.6W; Actual: 35.0N 69.5W; Error: 6 miles—152.0 hours in advance 40.0N 63.5W; Actual: 40.0N 64.1W; Error: 32 miles—172.5 hours in advance From September 5, 2011: 11:00 pm 30.0N 70.0W; Actual: 30.0N 69.8W; Error: 12 miles—43.0 hours in advance 35.0N 69.6W; Actual: 35.0N 69.5W; Error: 6 miles—66.5 hours in advance 40.0N 63.5W; Actual: 40.0N 64.1W; Error: 32 miles—87.0 hours in advance Link to comment Share on other sites More sharing options...
phlwx Posted September 9, 2011 Share Posted September 9, 2011 Verification: Track Estimates: From September 2, 2011: 9:30 am 17.5N 52.8W; Actual: 17.5N 52.4W; Error: 26 miles—1.0 hour in advance 20.0N 58.6W; Actual: 20.0N 57.0W; Error: 13 miles—33.0 hours in advance 25.0N 63.9W; Actual: 25.0N 63.7W; Error: 13 miles—77.5 hours in advance 30.0N 72.0W; Actual: 30.0N 69.8W; Error: 132 miles—129.5 hours in advance 35.0N 69.6W; Actual: 35.0N 69.5W; Error: 6 miles—152.0 hours in advance 40.0N 63.5W; Actual: 40.0N 64.1W; Error: 32 miles—172.5 hours in advance From September 5, 2011: 11:00 pm 30.0N 70.0W; Actual: 30.0N 69.8W; Error: 12 miles—43.0 hours in advance 35.0N 69.6W; Actual: 35.0N 69.5W; Error: 6 miles—66.5 hours in advance 40.0N 63.5W; Actual: 40.0N 64.1W; Error: 32 miles—87.0 hours in advance Don S. always kills it on track. Kudos. Link to comment Share on other sites More sharing options...
phil882 Posted September 9, 2011 Share Posted September 9, 2011 Don S. always kills it on track. Kudos. Yea nice work Don. Your max intensity forecast was spot on too. Link to comment Share on other sites More sharing options...
donsutherland1 Posted September 10, 2011 Share Posted September 10, 2011 Thanks all for the kind words. Link to comment Share on other sites More sharing options...
Fozz Posted September 10, 2011 Share Posted September 10, 2011 Apparently Katia is now extratropical. Link to comment Share on other sites More sharing options...
Amped Posted September 10, 2011 Share Posted September 10, 2011 Apparently Katia is now extratropical. Damit, that would have been the first 50mph+ moving hurricane since I've been alive 11:00 AM AST Sat Sep 10 Location: 44.7°N 47.7°W Max sustained: 80 mph Moving: ENE at 53 mph Min pressure: 954 mb Link to comment Share on other sites More sharing options...
on_wx Posted September 10, 2011 Share Posted September 10, 2011 The Met Office has warnings up now for the UK Amber Alert of Wind 12 Sep 2011, 00:00 Amber Alert of Wind Valid From: 12 Sep 2011, 00:00 Valid To: 12 Sep 2011, 23:59 Issued at - 10 Sep 2011, 11:38 Valid from - 12 Sep 2011, 00:00 Valid to - 12 Sep 2011, 23:59 The remains of Hurricane Katia are expected to come across the UK on Monday bringing a spell of wet and very windy weather. There remains some uncertainty about its track and intensity, although Scotland and Northern Ireland are most likely to bear the brunt of the winds, The public should be prepared for the risk of disruption to transport and of the possibility of damage to trees and structures. Yellow Alert of Wind 12 Sep 2011, 00:00 Yellow Alert of Wind Valid From: 12 Sep 2011, 00:00 Valid To: 12 Sep 2011, 23:59 Issued at - 10 Sep 2011, 11:38 Valid from - 12 Sep 2011, 00:00 Valid to - 12 Sep 2011, 23:59 The remains of Hurricane Katia are expected to come across the UK on Monday bringing a spell of wet and very windy weather. There remains some uncertainty about its track and intensity, although Scotland and Northern Ireland are most likely to bear the brunt of the winds, The public should be prepared for the risk of disruption to transport and of the possibility of damage to trees and structures. Link to comment Share on other sites More sharing options...
phlwx Posted September 12, 2011 Share Posted September 12, 2011 Wind gusts to 72 mph in the mountainous terrain of Wales so far from Katia's extrop remnants per the UK Met Office. Got a little bit of rain so far as well. http://www.metoffice.gov.uk/weather/uk/uk_latest_radar.html Link to comment Share on other sites More sharing options...
phlwx Posted September 12, 2011 Share Posted September 12, 2011 The deep area of low pressure which contains post-tropical cyclone Katia was at 0900 BST centred approximately 200 miles northwest of Sligo, Ireland with a central pressure of 966 hpa. Winds are strengthening, currently meaning 55 mph with a recent gust of 82 mph at Capel Curig in the mountains of North Wales. Elsewhere winds are widely gusting to 40 to 50 mph, with further strengthening expected across some northern areas through today. http://www.metoffice.gov.uk/weather/uk/uk_latest_wind.html Link to comment Share on other sites More sharing options...
Amped Posted September 12, 2011 Share Posted September 12, 2011 <H3>Severe gales affecting parts of the UKWinds are currently increasing over parts of central and southern Scotland and northern England with winds gusting 60 to 70 mph in places. Latest gusts include; 76 mph at Edinburgh Blackford Hill, 72 mph at Glasgow Bishopton and 71 mph at Loftus, North Yorkshire. The next few hours will see winds continuing to gust 60 to 70 mph in these areas with a few isolated gusts reaching 75 mph. Winds will slowly ease overnight. Keep up to date with the latest warnings using the link below. Issued at 1638 on Mon 12 Sep 2011. </H3> Link to comment Share on other sites More sharing options...
Ed Lizard Posted September 13, 2011 Share Posted September 13, 2011 Post-Tropical Hurricane Katia worst storm to hit UK in a decade Link to comment Share on other sites More sharing options...
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