[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 072358
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI AUG 07 2015

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
2315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 10N32W TO 20N31W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH A RELATIVELY SHARP 700 MB TROUGH
BETWEEN 28W-35W. THIS AREA OF TROUGHING WAS PREVIOUSLY THE LOW-
LEVEL MONSOON GYRE THAT WAS LOCATED ALONG THE MONSOON TROUGH THE
PAST FEW DAYS AND HAS NOW STARTED TO LIFT NORTHWARD DUE TO AN
UPPER LEVEL LOW CENTERED TO THE W-NW NEAR 24N34W. NO SIGNIFICANT
CONVECTION IS OCCURRING WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 09N46W TO 16N48W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING OVER THE
CENTRAL TROPICAL ATLC THAT CONTINUES WESTWARD AS LOW-AMPLITUDE
ENERGY THAT LACKS ANY SIGNIFICANT CONVECTION.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
19N67W TO 10N32W TO 10N43W TO 09N47W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 09N47W TO 10N60W. ISOLATED
MODERATE CONVECTION IS FROM 08N-11N BETWEEN 54W-57W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL SHORTWAVE
TROUGH IS OVER THE OFFSHORE WATERS OF THE CAROLINAS THAT EXTENDS
AN AXIS SW OVER NORTHERN FLORIDA AND THE NE GULF TO 26N87W. IN
ADDITION...ANOTHER SHORTWAVE IS NOTED OVER ALABAMA SLIDING
SOUTHEASTWARD THIS EVENING. WITH MIDDLE TO UPPER LEVEL TROUGHING
IN PLACE ACROSS THE NE GULF AND PORTIONS OF FLORIDA...SCATTERED
SHOWERS AND TSTMS ARE OCCURRING PRIMARILY ACROSS INLAND PORTIONS
OF NORTHERN FLORIDA AND THE ADJACENT COASTAL WATERS OF THE
FLORIDA BIG BEND REGION. OTHERWISE...THE REMAINDER OF THE GULF
IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1018 MB
HIGH CENTERED NEAR 25N87W. SKIES REMAIN MOSTLY CLEAR WITH FAIR
CONDITIONS EXPECTED THROUGH THE EVENING AND OVERNIGHT HOURS. THE
RIDGE SUPPORTS GENERALLY GENTLE TO MODERATE BREEZE CONDITIONS
THAT ARE EXPECTED TO PERSIST THROUGH SUNDAY AS THE RIDGE REMAINS
QUASI-STATIONARY.

CARIBBEAN SEA...
MUCH OF THE CARIBBEAN IS UNDER THE INFLUENCE OF WEST-NORTHWEST
FLOW ALOFT AND RELATIVELY STRONG SUBSIDENCE ALOFT. WATER VAPOR
IMAGERY INDICATES ONLY A VERY BROAD BASE TO A SW NORTH ATLC
TROUGH LIES OVER THE GREATER ANTILLES THIS EVENING HELPING TO
GENERATE ENOUGH LIFT FOR SCATTERED SHOWERS AND TSTMS ASSOCIATED
WITH PEAK DAYTIME HEATING AND INSTABILITY. THIS ACTIVITY WILL
LIKELY DIMINISH THROUGH THE LATE EVENING INTO THE EARLY
OVERNIGHT HOURS. OTHERWISE...THE PRIMARY MARINE IMPACT REMAINS
FRESH TO STRONG TRADES GENERALLY ACROSS THE CENTRAL CARIBBEAN
WITH GENTLE TO MODERATE TRADES ELSEWHERE.

...HISPANIOLA...
A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE ISLAND
THIS EVENING...BUT THIS ACTIVITY IS LIKELY TO DIMINISH THROUGH
THE EVENING HOURS DUE TO A LACK OF DAYTIME HEATING AND OVERALL
INSTABILITY. SKY CONDITIONS SHOULD CONTINUE TO IMPROVE DURING
THE OVERNIGHT HOURS INTO SATURDAY AS UPPER LEVEL TROUGHING MOVES
OVER THE ISLAND FROM THE NORTH THAT CONTAINS VERY DRY AIR.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR
IMAGERY OVER THE EASTERN SEABOARD WATERS WITH AXIS EXTENDING
FROM 34N76W TO A BASE IN THE EASTERN GULF OF MEXICO NEAR 26N87W.
THE TROUGHING SUPPORTS A RELATIVELY LARGE AND BROAD AREA OF LOW
PRESSURE FOCUSED ON A 1008 MB LOW CENTERED NEAR 37N72W AND A
1007 MB LOW CENTERED ACROSS EASTERN NORTH CAROLINA NEAR 35N78W.
LOW-LEVEL MOISTURE CONVERGENCE ALONG WITH MIDDLE TO UPPER LEVEL
DIFFLUENCE CONTINUES TO GENERATE SCATTERED SHOWERS AND TSTMS
ACROSS THE FAR WESTERN SW NORTH ATLC N OF 27N W OF 73W.
OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC IS UNDER THE
INFLUENCE OF A SURFACE RIDGE AXIS EXTENDING ALONG 26N BETWEEN
66W-82W PROVIDING MOSTLY CLEAR SKIES AND FAIR CONDITIONS THIS
EVENING. FARTHER EAST...A CUT-OFF UPPER LEVEL LOW IS CENTERED
NEAR 25N63W THAT SUPPORTS ISOLATED SHOWERS AND POSSIBLE ISOLATED
TSTMS FROM 23N-29N BETWEEN 55W-64W. OTHERWISE...THE REMAINDER OF
THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1030 MB HIGH NORTH OF THE DISCUSSION AREA
CENTERED NEAR 43N22W.

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

$$
HUFFMAN
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