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Atlantic Tropical Action 2014


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TD #2 now. Only forecast to be 30kts:

000WTNT22 KNHC 212031TCMAT2TROPICAL DEPRESSION TWO FORECAST/ADVISORY NUMBER   1NWS NATIONAL HURRICANE CENTER MIAMI FL       AL0220142100 UTC MON JUL 21 2014THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.INTERESTS IN THE LESSER ANTILLES SHOULD MONITOR THE PROGRESS OFTHIS SYSTEM.TROPICAL DEPRESSION CENTER LOCATED NEAR 11.6N  43.8W AT 21/2100ZPOSITION ACCURATE WITHIN  30 NMPRESENT MOVEMENT TOWARD THE WEST OR 280 DEGREES AT  14 KTESTIMATED MINIMUM CENTRAL PRESSURE 1012 MBMAX SUSTAINED WINDS  30 KT WITH GUSTS TO  40 KT.WINDS AND SEAS VARY GREATLY IN EACH QUADRANT.  RADII IN NAUTICALMILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.REPEAT...CENTER LOCATED NEAR 11.6N  43.8W AT 21/2100ZAT 21/1800Z CENTER WAS LOCATED NEAR 11.5N  43.1WFORECAST VALID 22/0600Z 11.9N  45.8WMAX WIND  30 KT...GUSTS  40 KT.FORECAST VALID 22/1800Z 12.3N  48.2WMAX WIND  30 KT...GUSTS  40 KT.FORECAST VALID 23/0600Z 12.8N  51.0WMAX WIND  30 KT...GUSTS  40 KT.FORECAST VALID 23/1800Z 13.4N  54.2WMAX WIND  30 KT...GUSTS  40 KT.FORECAST VALID 24/1800Z 15.0N  61.0W...POST-TROP/REMNT LOWMAX WIND  30 KT...GUSTS  40 KT.EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NMON DAY 4 AND 200 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAYOUTLOOK VALID 25/1800Z...DISSIPATEDREQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 11.6N  43.8WNEXT ADVISORY AT 22/0300Z$$FORECASTER BRENNAN
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Not a bright future is forecasted, but I think there's a real chance for TD #2 to get to 35+kts in the next 24 hours. Shear is very low...and will continue to be so for 24+ hours. It's moving at quite a brisk pace, but nothing disruptive yet. Thermodynamics is the real issue coupled with very dry air around it, so the convective process will be of the shallow type...but at least there won't be real shear to blow it off.

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Not a bright future is forecasted, but I think there's a real chance for TD #2 to get to 35+kts in the next 24 hours. Shear is very low...and will continue to be so for 24+ hours. It's moving at quite a brisk pace, but nothing disruptive yet. Thermodynamics is the real issue coupled with very dry air around it, so the convective process will be of the shallow type...but at least there won't be real shear to blow it off.

 

Yeah, we my have set a new record for mid-level dry air over the MDR for July 1-18.

 

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Not a bright future is forecasted, but I think there's a real chance for TD #2 to get to 35+kts in the next 24 hours. Shear is very low...and will continue to be so for 24+ hours. It's moving at quite a brisk pace, but nothing disruptive yet. Thermodynamics is the real issue coupled with very dry air around it, so the convective process will be of the shallow type...but at least there won't be real shear to blow it off.

 

I agree.. The shear is still relatively low right now, so the dry air shouldn't completely overwhelm the circulation in the short term (which is why its been able to organize and develop the last couple of days). Beyond 24 hours though, the low-level flow should start to accelerate as the storm approaches the Caribbean. At the same time, the upper-level diffluence (which has been aided by the passage of a Kelvin wave) will no longer be present, and the low-level circulation is likely to "run away" from its convective plume in the medium range. This scenario is similar to Dorian and Chantal last year which experienced similar problems after initial organization.

 

The mid-level relatively humidity forecasted by the SHIPS model is a ghastly 38% at 48 hours. Any amount of vertical wind shear (even if relatively light) could be the nail in this TD#2's coffin as it departs the moist cocoon of the monsoon trough. 

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In light of this, why is SHIPS insistent on continuous strengthening into the medium range?

 

...00 HRS... ...12 HRS... ...24 HRS... ...36 HRS...
140721 1800 140722 0600 140722 1800 140723 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 11.5N 43.1W 12.0N 46.0W 12.4N 49.0W 12.7N 52.1W
BAMD 11.5N 43.1W 11.8N 46.1W 12.1N 49.0W 12.3N 51.7W
BAMM 11.5N 43.1W 12.2N 45.7W 12.9N 48.4W 13.4N 51.3W
LBAR 11.5N 43.1W 11.9N 46.4W 12.6N 50.2W 13.3N 54.0W
SHIP 30KTS 36KTS 43KTS 49KTS
DSHP 30KTS 36KTS 43KTS 49KTS

...48 HRS... ...72 HRS... ...96 HRS... ..120 HRS...
140723 1800 140724 1800 140725 1800 140726 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 13.1N 55.5W 14.8N 63.2W 17.7N 71.0W 20.0N 77.4W
BAMD 12.5N 54.4W 13.1N 59.9W 14.6N 65.3W 16.7N 71.0W
BAMM 13.9N 54.3W 15.6N 60.4W 18.2N 65.7W 20.8N 70.0W
LBAR 14.1N 57.6W 15.8N 63.7W 17.6N 67.9W 0.0N 0.0W
SHIP 54KTS 62KTS 64KTS 67KTS
DSHP 54KTS 62KTS 64KTS 65KTS

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In light of this, why is SHIPS insistent on continuous strengthening into the medium range?

 

 

 

 

 

The SHIPS has been too strong with these systems in very dry environments the last few years.

It was consistently too strong for storms like Dorian and Erin among others last year.

...DORIAN SHOULD BE MOVING FAST ENOUGH THAT UPWELLING OFCOOLER WATER SHOULD NOT BE MUCH OF A FACTOR.  THEREFORE...THE NEWNHC INTENSITY FORECAST NO LONGER SHOWS SHORT-TERM WEAKENING ANDINSTEAD INDICATES SLIGHT STRENGTHENING THROUGH DAY 5.  THISFORECAST IS JUST A LITTLE HIGHER THAN THE FLORIDA STATESUPERENSEMBLE AND THE INTENSITY CONSENSUS...BUT NOT NEARLY AS HIGHAS THE STATISTICAL-DYNAMICAL SHIPS AND LGEM MODELS.  CONFIDENCE INTHE INTENSITY FORECAST IS RATHER LOW AT THIS POINT UNTIL WE KNOWHOW DORIAN FARES OVER THE NEXT DAY OR TWO.

Future Erin

THE DEPRESSION IS CURRENTLY IN AN ENVIRONMENT OF WARM SEA SURFACETEMPERATURES AND LIGHT VERTICAL WIND SHEAR.  THIS SHOULD ALLOW SOMESTRENGTHENING UNTIL THE SYSTEM REACHES COOLER WATERS IN 48 HR ORSO.  WHILE THE CYCLONE IS FORECAST TO LEAVE THE COOLER WATERS AFTERTHAT TIME...THE GFS...ECMWF...AND UKMET ARE IN GOOD AGREEMENT THATIT SHOULD ENCOUNTER VERY DRY AIR AND WEAKEN...WITH THESE MODELSSHOWING THE SYSTEM DEGENERATING TO A TROPICAL WAVE BY 120 HR.  THENEW INTENSITY FORECAST DOES NOT YET FOLLOW THAT SCENARIO...AS THESHIPS AND LGEM MODELS SHOW A STEADY-STATE OR STRENGTHENING SYSTEM. INSTEAD...THE FORECAST CALLS FOR A SLOW WEAKENING AS A COMPROMISEBETWEEN THESE EXTREMES.
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looks like some easterly shear is blowing that complex off the center.

Exactly, the strong easterly trades is pushing the thunderstorm complex off of the LLC (which looks very weak itself).  It's only going to continue to race westward which won't help with organization.  Plus, banding features are nonexistent.  

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In the meantime, there is a fairly well-organized continental low that may continue to move south over the gulf.  There are not currently any systems on the way to move or interact with it.  Was this low already forecast to develop and move in this direction?

 

1ik4dx.jpg

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We have ourselves a dedicated upper level low watcher. Maybe one out of 80 ULLs actually become anything during an entire season.

 

Yes :ph34r::)   I try to write my posts so that they do not gravitate towards "will this low somehow become tropical" and mention about observing their development and movement, as they can be unique! 

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Yes :ph34r::)   I try to write my posts so that they do not gravitate towards "will this low somehow become tropical" and mention about observing their development and movement, as they can be unique! 

May be, but your posts don't really tell us a lot unless you combine the observation with solid meteorology as to why it has that chance to be the once a season transitioning ULL to a tropical low.  Otherwise, we can all see the satellite photos and determine the importance.  

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Exactly, the strong easterly trades is pushing the thunderstorm complex off of the LLC (which looks very weak itself).  It's only going to continue to race westward which won't help with organization.  Plus, banding features are nonexistent.  

 

The low-level circulation is actually decently healthy if you want to believe the last few microwave images (check out that low-level cyan ring). The problem is that the shear vector is already starting to shift more out of a direction that will be advecting dry air into the core. The currently northerly shear is not helping the convective structure today, and as the shear vector continues to shift more out of the west, the storm will struggle to maintain deep convection even in its inner core. Without the convection aiding in the generation of low-level vorticity, the circulation will elongate and open up into a trough. 

 

tIKsD5C.jpg

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Does anyone know why we had so many TUTTs / such strong shear south of 30° N in August/September of last season, when there were few other negative factors? We had neutral-cool ENSO, but Niño-like shear in the central Atlantic. The pattern first started showing up in July last year, and now I'm seeing the same TUTT-dominated pattern showing up in the long-range models as we head into August. We also had this same pattern to a lesser extent in 2011 and (more so) 2012.

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Does anyone know why we had so many TUTTs / such strong shear south of 30° N in August/September of last season, when there were few other negative factors? We had neutral-cool ENSO, but Niño-like shear in the central Atlantic. The pattern first started showing up in July last year, and now I'm seeing the same TUTT-dominated pattern showing up in the long-range models as we head into August. We also had this same pattern to a lesser extent in 2011 and (more so) 2012.

Weaker Hadley cell correlation possible?

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How can I make a cross-section of the 850-250 mb vector winds delimited by 40° N highest latitude, EQ lowest latitude, Prime Meridian easternmost longitude, and 100° W westernmost longitude? I'm trying to find the Aug.-Sept. shear values for 2004-2005 and 2011-2013. Thanks.

 

http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl

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TD#2 is probably an open wave now... most of the microwave passes since yesterday have provided little evidence a closed circulation still exists. The convection that existed during the diurnal maximum has collapsed and first light visible appears to be confirming the system has degenerated into a shear axis.

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In the words of Kirsten Dunst, "Goodnight sweet prince"

 

BULLETIN
REMNANTS OF TWO ADVISORY NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL022014
1100 AM AST WED JUL 23 2014

...DEPRESSION DEGENERATES INTO A TROPICAL WAVE...
...THIS IS THE LAST ADVISORY...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...14.0N 56.0W
ABOUT 365 MI...590 KM ESE OF THE LESSER ANTILLES
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 25 MPH...41 KM/H
MINIMUM CENTRAL PRESSURE...1012 MB...29.89 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1100 AM AST...1500 UTC...THE CENTER OF THE REMNANTS OF TROPICAL
DEPRESSION TWO WAS LOCATED NEAR LATITUDE 14.0 NORTH...LONGITUDE 56.0
WEST.  THE REMNANTS ARE MOVING QUICKLY WESTWARD AT 25 MPH...41 KM/H.
THIS SYSTEM SHOULD MOVE THROUGH THE LESSER ANTILLES THIS EVENING.

MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/H...WITH HIGHER
GUSTS.  THIS SYSTEM SHOULD CONTINUE TO WEAKEN OVER THE NEXT DAY OR
SO.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1012 MB...29.89 INCHES.


HAZARDS AFFECTING LAND
----------------------
WIND...GUSTY WINDS ARE POSSIBLE ACROSS PORTIONS OF THE
WINDWARD AND LEEWARD ISLANDS TONIGHT AND EARLY THURSDAY.


NEXT ADVISORY
-------------
THIS IS THE LAST PUBLIC ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER ON THIS SYSTEM. ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE
FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER
SERVICE...UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.

 

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How can I make a cross-section of the 850-250 mb vector winds delimited by 40° N highest latitude, EQ lowest latitude, Prime Meridian easternmost longitude, and 100° W westernmost longitude? I'm trying to find the Aug.-Sept. shear values for 2004-2005 and 2011-2013. Thanks.

 

http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl

Not exactly what you asked for, but it may help:

 

http://rammb.cira.colostate.edu/projects/gparm/data/archived/

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