[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211130
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI MAR 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
1130 UTC.

...SPECIAL FEATURE...

A GALE WARNING IS IN EFFECT FOR A PORTION OF THE SOUTHERN
CARIBBEAN SEA FROM 11N TO 13N BETWEEN 73W AND 77W AS HIGH PRES N
OF THE AREA INTERACTS WITH LOW PRES OVER NORTHERN COLOMBIA. SEAS
WITHIN THE WARNING AREA ARE FORECAST TO BE IN THE RANGE OF 9-13
...DIMINISHING TO 8 TO 11 FT LATER THIS MORNING AND CONTINUING
THROUGH SUN. THE GALE WINDS ARE FORECAST TO DIMINISH TO JUST
BELOW GALE FORCE LATER THIS MORNING AS THE HIGH PRES N OF THE
AREA SHIFTS EASTWARD. PLEASE SEE THE HIGH SEAS FORECAST UNDER
AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
AT THE COAST OF GUINEA-BISSAU...AND CONTINUES S TO 5N16W WHERE
LOW LEVEL WINDS SUGGEST THE ITCZ BEGINS AND CONTINUES TO SW TO
1N25W TO S OF THE EQUATOR NEAR 35W. SCATTERED MODERATE
CONVECTION IS WITHIN 120 NM S OF THE MONSOON TROUGH.

...DISCUSSION...

GULF OF MEXICO...
THE UPPER LONGWAVE TROUGH HAS SHIFTED TO E OF FLORIDA. IN IT
WAKE...BROAD UPPER HIGH PRES HAS BECOME THE DOMINANT FEATURE
COVERING THE ENTIRE GULF WITH THE ASSOCIATED ANTICYCLONE
CENTERED OVER SOUTHERN GUATEMALA. MODERATE SUBSIDENCE ALOFT HAS
USHERED IN DRY AND STABLE AIR THROUGHOUT...EXCEPT N OF 27N WHERE
SCATTERED TO BROKEN CIRRUS CLOUDS STREAMING EASTWARD ARE DUE TO
A JET STREAM BRANCH THAT STRETCHES FROM THE EASTERN PACIFIC ENE
ACROSS NORTHERN MEXICO...AND TO ACROSS THE FAR NE GULF WHERE
MAXIMUM JET CORE WINDS ARE IN THE 90-140 KT RANGE. THE PRESENT
DRY AND STABLE CONDITIONS ALOFT ARE KEEPING THE MOISTURE CONTENT
THROUGHOUT ALL ATMOSPHERIC LEVELS TO A MINIMUM. ONLY ISOLATED
SHOWERS ARE POSSIBLE OVER THE SOUTHERN PORTION OF THE GULF S OF
24N BETWEEN 87W-94W. REMNANT LOW-LEVEL MOISTURE FROM A PREVIOUS
FRONTAL BOUNDARY IS SEEN AS SCATTERED LOW CLOUDS WITH POSSIBLE
ISOLATED SHOWERS OVER AND NEAR THE YUCATAN CHANNEL...AND N TO
NEAR 24N. IR NIGHT CHANNEL SATELLITE IMAGERY SHOWS LOW
CLOUDINESS BANKED ALONG THE SIERRA MADRE MOUNTAINS OF  MEXICO.
SURFACE RIDGING IS PRESENT ELSEWHERE OVER THE GULF. THE RIDGE
IS FORECAST TO WEAKEN ON SAT IN RESPONSE TO A COLD FRONT
FORECAST TO MOVE INTO THE NW GULF WATERS LATE ON SUN.

CARIBBEAN...
A BROAD UPPER RIDGE COVERS THE CARIBBEAN AND EXTENDS N OVER THE
GULF OF MEXICO AND WESTERN ATLC ANCHORED BY AN ANTICYCLONE OVER
SOUTHERN GUATEMALA. SATELLITE WATER VAPOR IMAGERY SHOWS DRY
STABLE AIR AT THE MID AND UPPER LEVELS ACROSS THE ENTIRE BASIN.
A DISSIPATING STATIONARY FRONT EXTENDING FROM THE WESTERN ATLC
SW TO CENTRAL AND WESTERN CUBA. PATCHES OF RESIDUAL SURFACE TO
LOW-LEVEL MOISTURE FROM THIS FRONT IS ONLY GENERATING ISOLATED
SHOWERS TO THE LEE OF CUBA BETWEEN 77W-81W. SIMILAR MOISTURE
PATCHES WITH POSSIBLE ISOLATED SHOWERS ARE MOVING WSW IN THE
TRADE WIND FLOW BETWEEN HAITI AND THE NE COAST OF HONDURAS. THE
REMAINDER OF THE CARIBBEAN IS UNDER THE INFLUENCE OF THE UPPER
RIDGE WITH RATHER DRY AND STABLE CONDITIONS NOTED. A MID/UPPER
LEVEL TROUGH...THE TAIL END OF THE ATLC TROUGH DESCRIBED
BELOW...IS OVER THE FAR EASTERN CARIBBEAN IN THE VICINITY OF THE
LESSER ANTILLES IS ABOUT STATIONARY FOR THE TIME BEING. THE
PRESENCE OF DRY AND STABLE AIR THROUGHOUT IS ONLY ALLOWING FOR
ISOLATED SHOWERS MOVING NW TO EXIST OVER THE FAR NE CARIBBEAN.
THIS TROUGH IS FORECAST TO MOVE SLOWLY EASTWARD ON SAT WHILE
DAMPENING OUT.

FRESH TO LOCALLY STRONG TRADE WINDS WILL PERSIST ACROSS THE
S/CENTRAL CARIBBEAN THROUGH THE WEEKEND WITH HIGHEST WINDS
OCCURRING NEAR THE COAST OF COLOMBIA DURING LATE NIGHT AND EARLY
MORNING HOURS. MODERATE TO LOCALLY FRESH TRADE WINDS WILL
PREVAIL ELSEWHERE...EXCEPT FOR A GENTLE TO MODERATE BREEZE IN
THE NW CARIBBEAN.

HISPANIOLA...
LATEST SATELLITE IMAGERY SHOWS MAINLY SCATTERED LOW CLOUDS OVER
THE MUCH OF THE CENTRAL AND WESTERN PORTIONS OF THE ISLAND.
ISOLATED SHOWERS ARE POSSIBLE IN SOME LOCATIONS. WITH AMPLE DRY
AIR ALOFT AS SEEN IN THE VAPOR IMAGERY...LOW-LEVEL MOISTURE IS
FORECAST TO REMAIN AT A MINIMUM THROUGH THE NEXT 24-48 HRS WITH
THE EXCEPTION OF SHOWER ACTIVITY THAT FORMS WITH AFTERNOON
HEATING.

ATLANTIC...
THE BROAD UPPER RIDGE OBSERVED OVER THE CARIBBEAN EXTENDS NEWD
OVER TO ACROSS THE WESTERN ATLC. A LONGWAVE TROUGH TYPE FEATURE
ENTERS THE AREA THROUGH 32N77W...AND EXTENDS TO NEAR THE
NORTHERN BAHAMAS. THE SURFACE COLD FRONT IS N OF THE
AREA...EXTENDING SW TO NEAR 31N70W. MOSTLY BROKEN TO OVERCAST
MID/UPPER CLOUDS WITH BROKEN LOW AND MID-LEVEL UNDERNEATH WITH
SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOTED WITHIN 180 NM E
OF THE FRONT. A WEAK MID/UPPER TROUGH IS SEEN EXTENDING FROM A
WEAK UPPER LOW NEAR 30N26W SW TO 24N40W TO 23N50W TO 16N60W AND
SW TO NE VENEZUELA. A WEAK COLD FRONT IS ANALYZED TO THE W OF
THIS TROUGH FROM NEAR 32N51W SW TO 28N56W...WHERE IT BECOMES
STATIONARY NW TO 29N35W...THEN SW TO 28N67W WHERE IT BEGINS TO
DISSIPATE TO THE CENTRAL BAHAMAS AND TO CENTRAL CUBA NEAR
22N78W. ISOLATED SHOWERS ARE WITHIN 60 NM OF THE FRONT E OF THE
BAHAMAS. THE REMAINDER OF THE ATLC E OF 68W IS DOMINATED BY A
BROAD SURFACE RIDGE ANCHORED BY A 1028 MB HIGH JUST N OF THE
AREA AT 33N29W. WEAKER HIGH PRES IS PRESENT W OF 68W WITH A 1017
MB HIGH AT 29N73W. ISOLATED SHOWERS ARE NOTED ON NWS RADAR TO BE
OVER THE WATERS BETWEEN THE BAHAMAS AND 80W. A WEAKER COLD FRONT
IS FORECAST TO SWEEP ACROSS THE NORTHERN PORTION OF THE WESTERN
ATLC FRI MERGING WITH THE SECOND FRONT DESCRIBED ABOVE WITH THE
MERGED FRONT DISSIPATING FROM NEAR 32N62W TO THE SOUTHERN
BAHAMAS BY SAT.

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

$$
AGUIRRE


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