[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 281805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUN 28 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.

...SPECIAL FEATURES...

AN ELONGATED MIDDLE LEVEL TROUGH ALONG THE WESTERN ATLC N OF 28N
SUPPORTS A WEAK LOW PRESSURE SYSTEM JUST OFF THE COAST OF SOUTH
CAROLINA. THIS AREA OF LOW PRESSURE IS SUPPORTING HEAVY SHOWERS
AND TSTMS N OF 26N BETWEEN 75W-80W. GRADUAL DEVELOPMENT OF THIS
SYSTEM IS EXPECTED IF ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE.
PLEASE SEE THE ATLC TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO
HEADERS MIATWOAT/ABNT20 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS EMBEDDED IN THE ITCZ WITH AXIS EXTENDING FROM
13N40W TO 5N40W MOVING W NEAR 25 KT. SSMI TPW AND SAHARAN AIR
LAYER TRACKING IMAGERY INDICATE THE PRESENCE OF DRY AIR N OF THE
ITCZ WHICH IS LIMITING THE CONVECTION TO SCATTERED SHOWERS
WITHIN 180 NM OF THE AXIS S OF 11N.

TROPICAL WAVE IS WEST OF THE ITCZ WITH AXIS EXTENDING FROM
18N53W TO 5N56W MOVING W-NW NEAR 15-20 KT. SAHARAN AIR LAYER
TRACKING IMAGERY SHOW DRY AIR IN THE WAVE ENVIRONMENT N OF 10N.
SCATTERED MODERATE CONVECTION IS LIMITED TO THE VICINITY OF THE
ITCZ FROM 6N-9N BETWEEN 54W-58W.

TROPICAL WAVE IS OVER THE CARIBBEAN WITH AXIS EXTENDING FROM
19N68W TO 6N71W MOVING W NEAR 15 KT. SSMI TPW IMAGERY SHOW DRY
AIR IN THE NORTHERN ENVIRONMENT OF THE WAVE WHICH ALONG STRONG
DEEP-LAYER WIND SHEAR OVER THE CENTRAL AND EASTERN CARIBBEAN
HINDER DEEP CONVECTION. SCATTERED SHOWERS ARE WITHIN 200 NM
EITHER SIDE OF THE AXIS S OF 15N.

TROPICAL WAVE IS OVER THE YUCATAN PENINSULA WITH AXIS EXTENDING
FROM 21N86W TO 14N90W MOVING W-NW NEAR 20 KT. THIS WAVE IS VERY
WEAK AND BARELY DISCERNIBLE AS IT MOVES IN THE W-SW PERIPHERY OF
A LOW LEVEL RIDGE. THERE IS NO CONVECTION ASSOCIATED WITH THIS
WAVE AT THE MOMENT.

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

THE MONSOON TROUGH EXTENDS FROM THE COAST GUINEA NEAR 10N14W TO
8N20W. THE ITCZ BEGINS NEAR 8N20W AND CONTINUES ALONG 7N30W TO E
OF A TROPICAL WAVE NEAR 7N38W. IT THEN RESUMES W OF THE WAVE
NEAR 6N42W TO 8N54W. SCATTERED MODERATE CONVECTION AND TSTMS ARE
FROM 6N-11N E OF 20W. SCATTERED MODERATE CONVECTION IS ALSO FROM
5N-7N BETWEEN 20W-28W AND FROM 4N-9N W OF 42W.

...DISCUSSION...

...THE GULF OF MEXICO...

SURFACE RIDGING DOMINATES ACROSS THE GULF BEING SUPPORTED BY A
MIDDLE LEVEL ANTICYCLONE COVERING THE WHOLE BASIN. THE SURFACE
RIDGE IS ANCHORED BY A 1022 MB HIGH NEAR 28N84W AND PROVIDES THE
GULF WITH E-SE WIND FLOW OF 10-15 KT...EXCEPT W OF 91W WHERE
WINDS ARE UP TO 20 KT. IN THE UPPER LEVELS...A TROUGH EXTENDS
ACROSS OKLAHOMA INTO EASTERN TEXAS TO THE NW GULF WHILE THE
EASTERN PERIPHERY OF A RIDGE ANCHORED OVER SW MEXICO COASTAL
WATERS COVERS THE BAY OF CAMPECHE. THIS WIND PATTERN ALOFT IS
GENERATING DIFFLUENCE TO SUPPORT SCATTERED SHOWERS W OF 92W.
HIGH PRESSURE WILL PREVAIL ACROSS THE BASIN FOR THE NEXT COUPLE
OF DAYS WHILE A TROPICAL WAVE MOVES ACROSS THE BAY OF CAMPECHE
TOWARDS THE SOUTHERN MEXICO AND THE E PACIFIC WATERS.

...THE CARIBBEAN SEA...

DRY AIR DOMINATES THE NORTHERN CARIBBEAN BASIN WHICH ALONG
STRONG DEEP-LAYER WIND SHEAR SUPPORT FAIR WEATHER N OF 15N. A
TROPICAL WAVE IS MOVING ACROSS THE CENTRAL BASIN. SEE THE WAVES
SECTION ABOVE FOR MORE DETAILS. OVER THE SW CARIBBEAN...THE
MONSOON TROUGH IS SUPPORTING SCATTERED SHOWERS S OF 14N W OF
75W. OTHERWISE...A SURFACE TROUGH IS NW OF THE WINDWARD ISLANDS
WITH AXIS EXTENDING FROM 15N61W TO 12N63W GENERATING SHOWERS S
OF 15N E OF 64W. THE PRESSURE GRADIENT BETWEEN THE ATLANTIC
RIDGE AND THE MONSOON TROUGH IS MAINTAINING 20-25 KT TRADES IN
THE CENTRAL CARIBBEAN AND 10-20 KT WINDS IN BOTH THE WESTERN AND
EASTERN CARIBBEAN. A NEW TROPICAL WAVE WILL BE ENTERING THE E
CARIBBEAN LATE SUNDAY.

...HISPANIOLA...

FAIR WEATHER AND CLEAR SKIES RULE OVER THE ISLAND SUPPORTED BY
DRY AIR AND STRONG DEEP-LAYER WIND SHEAR. SAHARAN DRY AIR WILL
CONTINUE TO MOVE OVER HISPANIOLA OVER THE NEXT COUPLE OF DAYS
AND DEVELOPMENT OF AFTERNOON CONVECTION SHOULD BE DELAYED...WITH
GENERALLY LESS COVERAGE THAN IS TYPICALLY EXPECTED DURING THE
SUMMER MONTHS.

...THE ATLANTIC OCEAN...

AN ELONGATED MIDDLE LEVEL TROUGH ALONG THE WESTERN ATLC N OF 28N
SUPPORTS A WEAK LOW PRESSURE SYSTEM JUST OFF THE COAST OF SOUTH
CAROLINA. THIS AREA OF LOW PRESSURE IS SUPPORTING HEAVY SHOWERS
AND TSTMS N OF 26N BETWEEN 75W-80W. SEE THE SPECIAL FEATURES
SECTION FOR MORE INFORMATION. AN UPPER LEVEL CYCLONIC
CIRCULATION CENTERED OVER THE NW CARIBBEAN EXTENDS A TROUGH AXIS
NORTHWARD TO SUPPORT ISOLATED SHOWERS AND TSTMS OVER THE CENTRAL
BAHAMAS...THE FLORIDA STRAITS AND PORTIONS OF EASTERN S FLORIDA.
FARTHER EAST...A SURFACE TROUGH EXTENDS FROM 28N61W TO 24N67W
WITH ISOLATED SHOWERS FROM 26N-28N BETWEEN 60W-65W.
OTHERWISE...A BROAD SURFACE RIDGE COVERS THE REMAINDER
BASIN...THUS SUPPORTING FAIR WEATHER.

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

$$
NR

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