[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211118
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI FEB 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURES...
A STRONG PRESSURE GRADIENT BETWEEN A BROAD SURFACE RIDGE OVER
THE NORTH ATLC EXTENDING INTO THE CARIBBEAN AND LOWER PRESSURE
ACROSS THE NORTHWESTERN SOUTH AMERICAN CONTINENT IS GENERATING
GALE FORCE NE WINDS IN CLOSE PROXIMITY TO THE COAST OF COLOMBIA
FROM 11N TO 13N BETWEEN 73W AND 77W WITH SEAS FROM 10 TO 15 FT.
THESE WEATHER CONDITIONS ARE FORECAST THROUGH SAT MORNING. SEE
LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS
MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
NEAR 9N14W AND CONTINUES TO 5N16W TO 3N20W. THE ITCZ BEGINS NEAR
3N20W AND CONTINUES TO 1N31W TO 0N41W TO 0S50W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 1S-3N BETWEEN 17W-
38W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH WITH AXIS EXTENDING FROM THE
UPPER TO LOWER MISSISSIPPI VALLEY SUPPORTS A FRONTAL SYSTEM THAT
ENTERS THE GULF AS A COLD FRONT FROM SOUTHERN MISSISSIPPI NEAR
30N89W TO SE LOUISIANA NEAR 29N90W TO 27N94W TO SOUTHERN TEXAS
NEAR 26N97W. THE TROUGH ALOFT ALSO SUPPORTS A PRE-FRONTAL TROUGH
FROM 31N86W TO 27N91W TO 24N96W. SSMI TPW IMAGERY SHOW MOISTURE
ADVECTION FROM THE CARIBBEAN REACHING THE NORTHERN GULF COAST. A
DEEP LAYER RIDGE WITH AXIS ALONG THE FAR WESTERN N ATLC IS
GENERATING DIFFLUENCE ALOFT OVER THE EASTERN U.S. WHICH ALONG
LOW-LEVEL MOISTURE CONVERGENCE SUPPORT A SWATH OF HEAVY SHOWERS
AND TSTMS FROM THE LOWER GREAT LAKES SW TO GEORGIA AND ALABAMA
INTO THE GULF N OF 26N BETWEEN 85W-90W. WATER VAPOR IMAGERY SHOW
MOSTLY DRY AIR IN THE MIDDLE LEVELS ACROSS THE REMAINDER GULF
WITH SOME UPPER LEVEL MOISTURE BEING ADVECTED FROM THE E PACIFIC
INTO THE WESTERN GULF BY WESTERLY FLOW. SURFACE RIDGING CONTINUE
TO EXTEND FROM THE ATLC INTO THE EASTERN GULF THUS PROVIDING
RETURN FLOW OF 15 KT ACROSS THIS PORTION OF THE BASIN...NE WIND
OF 25-30 KT IS OVER THE NW GULF EAST OF THE SURFACE TROUGH. THE
FRONT WILL CONTINUE TO MOVE SE TO EXTEND FROM TALLAHASSEE
FLORIDA SW TO THE BAY OF CAMPECHE LATER THIS MORNING. THE FRONT
IS EXPECTED TO STALL ACROSS NORTHERN FLORIDA AND THE EASTERN
GULF FRI NIGHT AND WILL START DISSIPATING BY SAT MORNING. A NEW
COLD FRONT IS EXPECTED TO ENTER THE NORTHERN GULF SUN NIGHT.

CARIBBEAN SEA...
NW TO W WIND FLOW ALOFT FROM THE NW TO EASTERN CARIBBEAN THIS
MORNING WITH WATER VAPOR IMAGERY INDICATING DRY AIR SUBSIDENCE
ACROSS THE ENTIRE BASIN. THIS DRY AIR SUPPORTS MOSTLY FAIR
WEATHER ACROSS THE REGION. HOWEVER...SCATTERED PASSING SHOWERS
ARE EXPECTED FOR PUERTO RICO...VIRGIN ISLANDS AND LEEWARD
ISLANDS ASSOCIATED WITH A WESTWARD MOVING MOIST AIRMASS
CURRENTLY OVER THE NE CARIBBEAN. SIMILAR CONVECTION IS FROM 11N-
16N BETWEEN 65W-83W. IN TERMS OF WIND...EASTERLY TRADES OF 20-25
KT DOMINATE ACROSS THE CENTRAL AND EASTERN BASIN WITH GALE FORCE
WINDS ALONG THE COAST OF COLOMBIA. GALE FORCE WINDS FOR THE
ABOVE MENTIONED REGION ARE EXPECTED TO CONTINUE THROUGH SAT
MORNING. SEE SPECIAL FEATURES SECTION FOR MORE DETAILS.

...HISPANIOLA...
CURRENTLY FAIR WEATHER CONDITIONS ON THE ISLAND BEING SUPPORTED
BY DRY AIR AT THE LOWER LEVELS AND ALOFT. HOWEVER...A MOIST
AIRMASS IS EXPECTED TO ENTER THE ISLAND LATER THIS MORNING WHICH
MAY ENHANCE SHALLOW CONVECTION. MODEL GUIDANCE INDICATE SKIES
MAY CLEAR OUT AGAIN SAT MORNING WITH THE ADVENT OF A LOWER LEVEL
DRY AIRMASS.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH EXTENDING FROM THE NORTH-CENTRAL ATLC SW
TO A BASE JUST NE OF THE DOMINICAN REPUBLIC SUPPORT A WEAK
SURFACE PRE-FRONTAL TROUGH ALONG 33N54W TO 30N58W TO 28N62W.
DIFFLUENT FLOW ALOFT SE OF THE TROUGH IS ENHANCING ISOLATED
SHOWERS N OF 24N BETWEEN 52W-60W. OTHERWISE...A BROAD SURFACE
RIDGE DOMINATES THE ENTIRE ATLC WATERS ANCHORED BY TWO HIGH
PRESSURE CENTERS...A 1028 MB HIGH NEAR 33N63W AND A 1033 MB HIGH
NEAR 36N24W. A WEAK COLD FRONT IS FORECAST TO ENTER THE SW N
ATLC FRI NIGHT AND DISSIPATE SAT NIGHT.

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

$$
NR


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