[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 181805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUN 18 2014

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...TROPICAL WAVES...
A NE TO SW TROPICAL WAVE EXTENDS FROM NEAR 06N54W TO 10N52W TO
14N49W MOVING W AT 18 KT. TOTAL PRECIPITABLE WATER IMAGERY
INDICATES A MAXIMUM IN THE VICINITY OF THE WAVE AXIS FROM 02N-
14N BETWEEN 44W-56W THAT COINCIDES WITH GLOBAL MODEL 850 MB
RELATIVELY VORTICITY GUIDANCE AND A WEAK 700 MB TROUGH AXIS. THE
WAVE IS PASSING UNDER A HOSTILE UPPER LEVEL ENVIRONMENT.
NUMEROUS DEEP CONVECTION OBSERVED 24 HRS AGO HAS DIMINISHED TO
WIDELY SCATTERED MODERATE CONVECTION FROM 10N TO 13N BETWEEN 50W-
54W.

TROPICAL WAVE IS ALONG 83W S OF 18W MOVING W AT 15 KT. THE 700
MB STREAMLINE FLOW PATTERN SUGGESTS THAT A CYCLONIC CIRCULATION
IS ALONG THE WAVE AT 13N83W WHERE A VORTICITY MAXIMUM HAS BEEN
NOTED THE PASSED FEW DAYS...AND HAS BEEN ENHANCING SCATTERED
SHOWER AND TSTMS ALONG AND JUST TO THE E OF HONDURAS AND
NICARAGUA. THIS CONVECTION IS DESCRIBED FURTHER BELOW UNDER
CARIBBEAN SEA.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST OF SENEGAL
NEAR 12N16W TO 09N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 09N20W TO 05N30W TO 05N40W TO 03N49W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM N OF THE
AXIS BETWEEN 26W-33W. SCATTERED MODERATE CONVECTION IS WITHIN
120 NM N OF THE ITCZ BETWEEN 33W-38W AND ALSO BETWEEN 43W-47W.

...DISCUSSION...

GULF OF MEXICO...
UPPER AIR WIND DATA DEPICTS NORTHERLY FLOW OVER MUCH OF THE GULF
BETWEEN A MID TO UPPER LEVEL TROUGH OVER THE SW NORTH ATLC AND
CUBA AND AN UPPER LEVEL RIDGE WITH AXIS ALONG 99W. WATER VAPOR
IMAGERY INDICATES MOST OF THIS NORTHERLY FLOW ALOFT REMAINS
RELATIVELY DRY AND STABLE...AND SUPPORTS A SURFACE RIDGE ACROSS
THE NORTHERN GULF. UNSTABLE AIR ALOFT IN COMBINATION WITH MOIST
AND UNSTABLE AIR AT THE LOWERS LEVELS IS AGAIN ALLOWING FOR THE
DEVELOPMENT OF SCATTERED TSTM ACTIVITY OVER THE FAR SE GULF FROM
23N TO 26N E OF 84W TO THE VICINITY OF FLORIDA KEYS. THIS
ACTIVITY IS EXPECTED TO CONTINUE THROUGH THE AFTERNOON AND
THROUGH TONIGHT AS UPPER FAVORABLE DIFFLUENT FLOW ALOFT PERSISTS.
OTHERWISE...THE RIDGE WILL CONTINUE TO DOMINATE THE WIND REGIME
THROUGH THU WITH E-SE WINDS IN THE RANGE OF ABOUT 10-15 KT...
EXCEPT FOR E WINDS 5-10 KT IN THE N CENTRAL AND SE PORTIONS.

CARIBBEAN SEA...
WATER VAPOR IMAGERY SHOWS THE SOUTHERN EXTENSION OF THE
MID/UPPER TROUGH E OF THE FLORIDA EXTENDING SSW TO HONDURAS. DRY
AIR AND ASSOCIATED SUBSIDENCE ARE PROMOTING FAIR WEATHER AT THE
SURFACE N OF 16N AND W OF A LINE FROM 21N79W TO 16N87W. TO THE
SE OF THE TROUGH...SOUTHWESTERLY FLOW QUICKLY BECOMES GENERALLY
WESTERLY FLOW OVER THE CENTRAL AND EASTERN CARIBBEAN WITH PLENTY
OF MIDDLE TO UPPER LEVEL CLOUDINESS AND DEEP LAYER MOISTURE.
MOST OF THE CONVECTION REMAINS CONCENTRATED TO THE SW CARIBBEAN
AND THE EASTERN PORTIONS OF HONDURAS AND NICARAGUA AS THE
TROPICAL WAVE ALONG 83W MOVES THROUGH THIS PART OF THE AREA
CONTRIBUTING TO INSTABILITY AND LOW-LEVEL CONVERGENCE THERE.
SCATTERED SHOWERS AND TSTMS ARE NOTED FROM 10N TO 16N BETWEEN
81W AND 83.5W. ALTHOUGH THE WAVE WILL CONTINUE ON WESTWARD
THROUGH THE NEXT 48 HRS...THE SCATTERED SHOWERS AND TSTMS WILL
REMAIN ACTIVE UNDER FAVORABLE UPPER LEVEL CONDITIONS E AND SE OF
THE AFOREMENTIONED MID/UPPER TROUGH. OTHERWISE...ELY TRADES
PERSIST GENERALLY IN THE RANGE OF 15 TO 25 KT WITH THE STRONGEST
WINDS NOTED FROM 11N-17N BETWEEN 68W-82W. STRONGER WINDS OF
25-30 KT ARE WITHIN 90 NM OF THE COAST OF COLOMBIA. THE OVERALL
SYNOPTIC PATTERN AND ASSOCIATED PRES GRADIENT IS EXPECTED TO
CHANGE LITTLE THROUGH THE NEXT 48 HRS WITH STRONG TRADES
CONTINUING ACROSS THE CENTRAL AND SW CARIBBEAN.

...HISPANIOLA...
CURRENTLY...SCATTERED LOW CLOUDS WITH ISOLATED SHOWERS ARE
OCCURRING ACROSS THE ISLAND AND NEARBY WATERS. BROKEN TO
SCATTERED HIGH CIRRUS CLOUDS ARE STREAMING EASTWARD ACROSS THE
ISLANDS AS WELL. SHOWER AND TSTMS IS EXPECTED TO AGAIN
MATERIALIZE ACROSS PORTIONS OF THE ISLAND...BUT SHOULD BE
LESS IN COVERAGE COMPARED TO PREVIOUS DAYS AS UPPER LEVEL
SUPPORT WILL BE LESS FAVORABLE.

ATLANTIC OCEAN...
WATER VAPOR IMAGERY SHOWS AN UPPER LOW CENTERED NEAR 27N64W WITH
A TROUGH AXIS EXTENDING SW TO NEAR 22N75W. THIS FEATURE SUPPORTS
A COLD FRONT ANALYZED FROM 32N56W SW TO 29N61W WHERE IT BECOMES
A WEAKENING STATIONARY FRONT TO 27N68W...AND A TROUGH FROM THERE
TO 27N73W TO 29N78W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE
ELSWHERE WITHIN 120 NM S AND SE OF THE STATIONARY FRONT AND
TROUGH...AND WITHIN 60 NM SE OF THE COLD FRONT. A WEAK SURFACE
TROUGH...SUPPORTED BY THE UPPER LOW...IS ALONG 27N63W 24N65W.
SCATTERED TSTM ARE NOTED BETWEEN THIS TROUGH AND STATIONARY
FRONT. OVER THE FAR WESTERN PORTION OF THE AREA...A MID TO UPPER
LOW LIFTING NNW IS JUST N OF THE AREA NEAR 31N78W WITH A TROUGH
SW TO WESTERN CUBA. DRIER AIR IS NOTED TO THE W AND SW OF THE
LOW. THESE FEATURES ARE ALLOWING UNSTABLE CONDITIONS TO CONTINUE
ALOFT...WHICH IN COMBINATION WITH VERY MOIST AIR AT THE SURFACE
AND LOW LEVELS WILL CONTINUE TO RESULT IN SCATTERED SHOWER AND
TSTMS ACROSS MUCH OF THE BAHAMAS AND VICINITY WATERS...AND WATERS
BETWEEN THE BAHAMAS AND FLORIDA. THIS ACTIVITY IS EXPECTED TO
CONTINUE INTO THU. OTHERWISE...THE REMAINDER OF THE SW NORTH
ATLC IS UNDER THE INFLUENCE OF HIGH PRES N OF 27N...ANCHORED BY
A 1023 MB HIGH CENTERED W OF BERMUDA NEAR 32N71W. THE HIGH IS
FORECAST TO MOVE E TO NEAR 32N63W BY THU MORNING. OVER THE
CENTRAL AND EASTERN ATLC...HIGH PRES IS THE DOMINATE FEATURE
THERE...ANCHORED BY A 1027 MB STATIONARY HIGH CENTER N OF THE
AREA AT 33N33W. SCATTERED TO BROKEN HIGH CLOUDS STREAMING
EASTWARD ARE NOTED FROM 10N TO 22N W OF 40W DUE TO A STRONG JET
STREAM BRANCH AHEAD OF THE AFOREMENTIONED UPPER TROUGH.
OTHERWISE...RATHER STABLE CONDITIONS PERSIST ACROSS THESE
PORTIONS OF THE ATLC.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
AGUIRRE


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