[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI MAY 13 2011

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
1715 UTC.

...ITCZ...

ITCZ AXIS IS ALONG 08N13W 04N26W TO 01N36W...THEN RESUMES NEAR
02N39W TO 02N50W. SCATTERED MODERATE CONVECTION IS FROM 02N-06N
BETWEEN THE PRIME MERIDIAN AND 12W...AND FROM THE EQUATOR TO 06N
BETWEEN 23W-44W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL LOW IS LOCATED OVER
WESTERN MISSOURI WITH AXIS EXTENDING INTO THE NORTH-CENTRAL GULF
FROM EASTERN LOUISIANA TO 28N89W. WHILE NO SPECIFIC FRONTAL
BOUNDARY IS LOCATED OVER THE NW GULF WATERS...A SUBTLE AND WEAK
WIND SHIFT IS NOTED OFF THE LOUISIANA COAST IN RECENT SHIP...
BUOY...AND OIL PLATFORM OBSERVATIONS. MIDDLE TO UPPER LEVEL
DIFFLUENCE EAST OF THE TROUGH AXIS IS GENERATING A LARGE AREA OF
CLOUDINESS OVER THE EASTERN GULF N OF 25N WITH ISOLATED SHOWERS
OCCURRING MAINLY N OF 27N BETWEEN 85W-90W. THE REMAINDER OF THE
GULF IS UNDER THE INFLUENCE OF NW FLOW ALOFT WITH MOSTLY DRY AIR
AND SUBSIDENCE NOTED ON WATER VAPOR IMAGERY W OF 90W AND S OF
23N W OF 90W. AT THE SURFACE...A 1016 MB HIGH IS CENTERED NEAR
27N84W AND IS FORECAST TO SLIDE EASTWARD INTO THE SW NORTH ATLC
OVER THE NEXT 24 TO 36 HOURS. THE NEXT COLD FRONT...CURRENTLY
DRAPED ACROSS NW LOUISIANA AND SE TEXAS...IS EXPECTED TO ENTER
THE NW GULF WATERS LATE TONIGHT INTO EARLY SATURDAY MORNING WITH
NORTHERLY WINDS IN THE RANGE OF 15 TO 20 KT.

CARIBBEAN SEA...
NORTHWEST TO WESTERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY
ACROSS A MAJORITY OF THE CARIBBEAN AS BROAD UPPER LEVEL
TROUGHING PROGRESSES ACROSS THE NORTH-CENTRAL PORTION OF THE
BASIN. RELATIVELY DRY AIR ALOFT ACCOMPANIES THE TROUGHING N OF
15N BETWEEN 65W-85W...WITH MOST UPPER LEVEL MOISTURE AND
CLOUDINESS SUPPRESSED S OF 13N OVER COSTA RICA...PANAMA...AND
NORTHERN SOUTH AMERICA. EAST OF THE UPPER LEVEL TROUGH AXIS
WHICH EXTENDS FROM OVER HISPANIOLA TO THE SW CARIBBEAN NEAR
13N81W...LOW-LEVEL MOISTURE...ASSOCIATED WITH A SURFACE TROUGH
ANALYZED FROM NEAR 20N66W THROUGH THE MONA PASSAGE TO 10N76W IS
GENERATING ISOLATED SHOWERS OVER THE CENTRAL CARIBBEAN FROM
15N-18N BETWEEN 67W-72W AND WIDELY SCATTERED SHOWERS AND
ISOLATED TSTMS N OF 17N E OF 67W. THIS SURFACE TROUGH HAS
DISRUPTED TYPICAL EASTERLY TRADES ACROSS THE CENTRAL PORTION OF
THE BASIN...AND GLOBAL MODEL GUIDANCE INDICATES THIS SYNOPTIC
SETUP WILL REMAIN IN PLACE OVER THE NEXT FEW DAYS AS A BROAD
DEEP LAYER LOW CONTINUES TO SPIN OVER PORTIONS OF THE WESTERN
NORTH ATLC. ELSEWHERE...SCATTERED SHOWERS AND ISOLATED TSTMS
CONTINUE OVER PORTIONS OF THE SW CARIBBEAN S OF 13N W OF 74W.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW IS CENTERED IN THE WESTERN NORTH ATLC NEAR
35N60W THAT SUPPORTS A MIDDLE TO UPPER LEVEL TROUGH AXIS
EXTENDING SW TO 30N63W TO 22N71W THEN INTO THE SW CARIBBEAN SEA.
A SURFACE TROUGH IS ANALYZED FROM NEAR 29N55W EXTENDING SW TO
THE TURKS AND CAICOS ISLANDS NEAR 22N72W. ISOLATED SHOWERS ARE
OCCURRING WITHIN 75 NM EITHER SIDE OF THE SURFACE TROUGH.
SOUTHWESTERLY UPPER LEVEL FLOW ALONG WITH THE WEAK SURFACE
BOUNDARY IS ALSO CONTINUING TO GENERATE A LARGE AREA OF WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 330 NM EITHER SIDE
OF A LINE FROM 31N45W TO 18N64W. ELSEWHERE E OF 45W...A MAJORITY
OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF SURFACE RIDGING
THAT EXTENDS AN AXIS ALONG 32N36W TO 15N37W. A WEAK SURFACE
TROUGH ANALYZED FROM 25N43W TO 21N45W IS EMBEDDED WITHIN THE
SURFACE RIDGE AND CONTINUES TO DRIFT SLOWLY W-NW. POSSIBLE
ISOLATED SHOWERS ARE FROM 21N-26N BETWEEN 40W-46W. LASTLY...AN
UPPER LEVEL LOW IS CENTERED NEAR 33N23W AND SUPPORTS A 1010 MB
SURFACE LOW CENTERED NORTH OF THE CANARY ISLANDS NEAR 30N16W. A
SURFACE TROUGH AXIS EXTENDS EASTWARD FROM THE LOW TO OVER
SOUTHERN MOROCCO NEAR 28N10W. NO SIGNIFICANT CONVECTION IS NOTED
ON SATELLITE IMAGERY WITH THIS LOW AND BOUNDARY.

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

$$
HUFFMAN



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