[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 252348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAY 25 2011

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
2315 UTC.

...ITCZ...

ITCZ AXIS IS ALONG 10N14W 05N24W 03N41W 04N50W. SCATTERED
MODERATE CONVECTION IS FROM 02N-07N BETWEEN 19W-36W. ISOLATED
MODERATE CONVECTION IS FROM 03N-05N BETWEEN 39W-42W. A SURFACE
TROUGH IS ANALYZED ON THE WESTERN EDGE OF THE AXIS FROM 05N-09N
ALONG 52W WITH NO SIGNIFICANT CONVECTION NOTED IN ITS VICINITY.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES MUCH OF THE GULF IS UNDER THE
INFLUENCE OF MODERATELY DRY AND SUBSIDENT W-NW FLOW ALOFT WHICH
IS RESULTING IN REMARKABLY CLOUDLESS SKIES THIS EVENING. A
SURFACE RIDGE AXIS EXTENDS FROM THE W ATLC ACROSS THE CENTRAL
FLORIDA PENINSULA TO THE TEXAS GULF COAST NEAR CORPUS CHRISTI
WITH MOSTLY E TO SE WINDS PREVAILING IN THE RANGE OF 10 TO 15
KT. WHILE SKIES REMAIN CALM IN A CONVECTIVE SENSE...THE LAST FEW
VISIBLE SATELLITE IMAGES OF THE DAY HOWEVER ARE STILL SHOWING A
HAZY ATMOSPHERE W OF 93W DUE TO THE ADVECTION OF SMOKE FROM
SOUTHERN MEXICO WILDFIRES. A SELECT FEW OFFSHORE OIL RIGS...AND
LAND-BASED AIRPORT METARS ACROSS TEXAS AND LOUISIANA ARE
REPORTING VISIBILITIES BELOW 10 STATUTE MILES...8.7 NM. THE
SURFACE RIDGE IS FORECAST TO REMAIN NEARLY STATIONARY ALONG THE
NORTHERN GULF WATERS THROUGH THE WEEKEND WITH SOUTHERLY RETURN
FLOW INCREASING BY SATURDAY AS ANOTHER STRONG LOW PRESSURE
SYSTEM DEVELOPS OVER THE U.S. CENTRAL PLAINS.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH AXIS EXTENDS FROM THE SW NORTH ATLC ACROSS
WESTERN CUBA INTO THE WESTERN CARIBBEAN TO HONDURAS. VERY DRY
AIR AND STRONG SUBSIDENCE IS ACROSS THE NW CARIBBEAN WHERE CLEAR
SKIES PREVAIL THIS EVENING. A FEW ISOLATED SHOWERS AND TSTMS ARE
OCCURRING OVER INTERIOR PORTIONS OF CUBA...HOWEVER THOSE ARE
EXPECTED TO DIMINISH OVER THE NEXT FEW HOURS DUE TO THE LOSS OF
PEAK DAYTIME HEATING. EAST OF THE UPPER LEVEL TROUGH AXIS...
MIDDLE TO UPPER LEVEL MOISTURE IS ADVECTING FROM THE SW
CARIBBEAN TO NORTHEAST OF HISPANIOLA. A SURFACE TROUGH IS
ANALYZED FROM NORTHERN COLOMBIA NEAR 11N75W TO 13N81W. ISOLATED
SHOWERS ARE OCCURRING IN THE VICINITY OF AND TO THE NORTHEAST OF
THE SURFACE TROUGH FROM 10N-20N BETWEEN 68W-81W. MEANWHILE...
LIGHT EASTERLY TRADEWIND FLOW PERSISTS ACROSS THE ENTIRE BASIN
WITH FAIR CONDITIONS AND MOSTLY CLEAR SKIES NOTED ACROSS THE FAR
EASTERN CARIBBEAN AND LESSER ANTILLES THIS EVENING.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH AXIS EXTENDS OVER THE SW NORTH ATLC ALONG
32N74W TO WESTERN CUBA NEAR 22N81W THEN INTO THE WESTERN
CARIBBEAN SEA. EAST OF THE TROUGH...THE REMAINDER OF THE SW
NORTH ATLC IS UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE WITH
AXIS ALONG 63W. DIFFLUENCE ALOFT BETWEEN THESE TWO UPPER LEVEL
FEATURES IS SUPPORTING THE ADVECTION OF MOISTURE FROM THE
CENTRAL CARIBBEAN SEA INTO THE W ATLC WITH ISOLATED SHOWERS AND
TSTMS OCCURRING FROM 19N-30N BETWEEN 62W-73W. OTHERWISE...A
SURFACE RIDGE EXTENDS SW FROM A 1019 MB HIGH CENTERED NW OF
BERMUDA NEAR 33N67W. FARTHER EAST...AN UPPER LEVEL LOW IS
CENTERED NEAR 29N47W AND SUPPORTS A FILLING 1011 MB SURFACE LOW
NEAR 27N56W. A SURFACE TROUGH WRAPS INTO THE LOW AND EXTENDS
ALONG 25N54W 23N58W TO 25N63W. ISOLATED SHOWERS ARE POSSIBLE
WITHIN 240 NM OF THE LOW CENTER. THE UPPER LEVEL LOW ALSO
SUPPORTS A FRONTAL TROUGH BOUNDARY ALONG 31N51W 28N46W 23N47W TO
19N58W THEN BECOMES A SHEAR LINE TO HISPANIOLA NEAR 19N70W.
LOW-LEVEL CONVERGENCE AND MIDDLE TO UPPER LEVEL DIFFLUENCE ARE
COMBINING TO GENERATE WIDELY SCATTERED SHOWERS AND ISOLATED
TSTMS FROM 18N-32N BETWEEN 37W-48W...INCLUDING WITHIN 90 NM
EITHER SIDE OF THE SHEAR LINE. THE REMAINDER OF THE EASTERN ATLC
IS UNDER THE INFLUENCE OF A SURFACE RIDGE EXTENDING SOUTHWARD
INTO THE DISCUSSION AREA ALONG 34W. FINALLY...AN UPPER LEVEL LOW
IS CENTERED OVER THE MADEIRA ISLANDS NEAR 33N17W. THIS DEEP
LAYER TROUGH REFLECTS AS A 1012 MB LOW CENTERED NEAR 33N17W WITH
A COLD FRONT WELL EAST ALONG 32N11W TO 27N18W ACROSS THE CANARY
ISLANDS. ISOLATED SHOWERS ARE OCCURRING WITHIN 240 NM EAST OF
THE FRONT...INCLUDING MUCH OF MOROCCO AND WESTERN SAHARA. ALSO
OF NOTE...THE CIMSS SAHARAN AIR LAYER TRACKING PRODUCT INDICATES
A SURGE OF AFRICAN DUST PRIMARILY FROM 10N-20N E OF 30W. THIS
DUST FILLED AND DRY AIR LAYER WAS EVIDENT ON THE EARLIER MORNING
SOUNDING AT DAKAR SENEGAL FROM ROUGHLY 975 MB UPWARDS TO 600 MB.

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

$$
HUFFMAN



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