[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 042356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON AUG 04 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURE...

THE CENTER OF HURRICANE BERTHA IS NEAR 29.4N 73.6W AT 04/2100 UTC
...OR ABOUT 486 NM WSW OF BERMUDA. BERTHA IS MOVING
NORTHWARD...OR 360 DEGREES...AT 16 KT. THE ESTIMATED MINIMUM
CENTRAL PRESSURE IS 998 MB. THE MAXIMUM SUSTAINED WIND SPEED IS
65 KT WITH GUSTS TO 80 KT. A CLUSTER OF MODERATE CONVECTION IS
FROM 27N-30N BETWEEN 72W-74W WITH RAINBANDS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ELSEWHERE FROM 24N-30N
BETWEEN 69W-76W. ISOLATED TSTMS ARE IN THE RAINBANDS OF THE SW
QUADRANT OF BERTHA. PLEASE READ THE LATEST NHC INTERMEDIATE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33 KNHC
AND THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS JUST EAST OF THE CAPE VERDE ISLANDS WITH AXIS
EXTENDING FROM 16N21W TO 9N21W MOVING W AT 10 KT. THE NORTHERN
WAVE ENVIRONMENT N OF 13N CONTINUES TO BE AFFECTED BY THE DRY
SAHARAN AIR LAYER WHICH IS INHIBITING CONVECTION IN THAT REGION.
ISOLATED SHOWERS ARE ELSEWHERE FROM 9N-13N E OF 25W.

TROPICAL WAVE IS ABOUT 200 NM E OF THE LESSER ANTILLES WITH AXIS
EXTENDING FROM 21N56W TO 11N57W MOVING W AT 20 KT. DRY SAHARAN
AIR CONTINUES TO AFFECT MOST OF THE WAVE ENVIRONMENT WHICH ALONG
STRONG DEEP LAYER ENVIRONMENTAL SHEAR INHIBIT CONVECTION AT THE
TIME.

TROPICAL WAVE IS OVER CARIBBEAN WATERS WITH AXIS EXTENDING FROM
18N66W TO 10N67W MOVING W AT 15 KT. NO DEEP CONVECTION IS
ASSOCIATED WITH THE WAVE DUE TO DRY AIR SUBSIDENCE FROM THE
MIDDLE AND UPPER LEVELS. ISOLATED SHOWERS ARE POSSIBLE FOR
COASTAL WATERS OF PUERTO RICO.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
14N16W TO 9N24W TO 8N37W. THE INTERTROPICAL CONVERGENCE ZONE
AXIS BEGINS NEAR 7N37W AND CONTINUES ALONG 6N46W TO 7N52W. IN
ADDITION TO THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVE...WIDELY SCATTERED SHOWERS ARE FROM 5N-10N BETWEEN 23W-30W.
SCATTERED MODERATE CONVECTION IS FROM 4N-7N BETWEEN 42W-49W.

...DISCUSSION...

GULF OF MEXICO...

THE WIND PATTERN IN THE MIDDLE TO UPPER LEVELS IS LEAVING A COL
OR AREA OF LOW PRESSURE NEAR THE CENTRAL GULF...THUS SUPPORTING
A 1014 MB LOW NEAR 26N91W WITH SCATTERED HEAVY SHOWERS AND TSTMS
FROM 23N-27N BETWEEN 88W-94W. A WEAKNESS IN THE SW PERIPHERY OF
A MIDDLE LEVEL RIDGE ANCHORED NEAR 32N64W IS SUPPORTING A
SURFACE TROUGH ACROSS THE FLORIDA PENINSULA WHICH IS ENHANCING
SCATTERED HEAVY SHOWERS AND TSTMS. THESE SHOWERS AND TSTMS
ACTIVITY EXTEND WITHIN 280 NM FROM THE WESTERN COAST OF FLORIDA
TO THE EASTERN GULF WATERS. AN INVERTED MIDDLE TO UPPER LEVEL
TROUGH OVER THE S-SW GULF SUPPORT A SURFACE TROUGH OVER THE
YUCATAN PENINSULA FROM 22N87W TO 16N90W AS WELL AS ISOLATED
HEAVY SHOWERS AND TSTMS THAT EXTEND WITHIN 60 NM FROM THE
NORTHERN AND WESTERN PENINSULA COASTLINE. OTHERWISE...VARIABLE
WINDS OF 5-10 KT DOMINATE ACROSS THE BASIN. THE AREA OF LOW
PRESSURE AND ASSOCIATED RAIN OVER THE FLORIDA PENINSULA IS
FORECAST TO MOVE NE TOWARDS ATLC WATERS TUE MORNING. HIGH
PRESSURE WILL THEN BUILD ACROSS THE GULF THROUGH THURSDAY.

CARIBBEAN SEA...

MODERATE DEEP LAYER MOISTURE IS OVER THE WESTERN AND SW
CARIBBEAN SEA WHICH ALONG MIDDLE TO UPPER LEVEL DIFFLUENT FLOW
SUPPORT SCATTERED SHOWERS AND TSTMS N OF 15N BETWEEN 79W-84W. IN
THE SW CARIBBEAN SEA...REMNANT SHOWERS ASSOCIATED WITH A FORMER
AREA OF LOW PRESSURE ARE S OF 14N. A TROPICAL WAVE IS MOVING OVER
THE EASTERN CARIBBEAN WITH NO CONVECTION ASSOCIATED WITH IT. SEE
THE TROPICAL WAVES SECTION ABOVE FOR MORE DETAILS. DRY AIR
SUBSIDENCE FROM ALOFT IS ACROSS THE REMAINDER BASIN...THUS
SUPPORTING CLEAR SKIES AND FAIR WEATHER. TRADES OF 10-15 KT
DOMINATE ACROSS THE BASIN WITH HIGHER WINDS UP TO 20 KT ALONG
THE COAST OF COLOMBIA AND COASTAL WATERS OF SOUTHERN HISPANIOLA.
TRADES ARE EXPECTED TO INCREASE 20-25 KT OVER THE CENTRAL BASIN
TUE DUE TO THE PASSAGE OF THE TROPICAL WAVE. A SECOND TROPICAL WAVE
IS EXPECTED TO ENTER THE EASTERN CARIBBEAN LATE TONIGHT.

...HISPANIOLA...

FAIR WEATHER AND CLEAR SKIES ARE ACROSS THE ISLAND SUPPORTED BY
DEEP LAYER DRY AIR. THESE CONDITIONS ARE EXPECTED TO PERSIST
THROUGH TUE AFTERNOON WHEN DAYTIME HEATING WILL SUPPORT SOME
SHOWERS.

ATLANTIC OCEAN...

THE HIGHLIGHT IN THE ATLC IS HURRICANE BERTHA DISCUSSED IN THE
SPECIAL FEATURES SECTION. A WEAKNESS IN THE SW PERIPHERY OF A
MIDDLE LEVEL RIDGE ANCHORED NEAR 32N64W IS SUPPORTING A SURFACE
TROUGH ACROSS THE FLORIDA PENINSULA WHICH IS ENHANCING SCATTERED
HEAVY SHOWERS AND TSTMS. THESE SHOWERS AND TSTMS ACTIVITY EXTEND
WITHIN 130 NM FROM THE EASTERN COAST OF FLORIDA TO THE SW N ATLC
WATERS. SIMILAR CONVECTION IS IN THE STRAITS OF FLORIDA AND CUBA
NORTHERN COASTAL WATERS. SHOWER ACTIVITY WILL CONTINUE OVER THE
SW N ATLC WATERS THROUGH WED AFTERNOON. OTHERWISE...BESIDES THE
TROPICAL WAVES ALREADY DISCUSSED...SURFACE RIDGING ANCHORED BY
SEVERAL HIGH PRESSURE CENTERS N OF 30N DOMINATES ELSEWHERE.

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

$$
NR


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