[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 272346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI MAY 27 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS FROM 04N TO 11N ALONG 52W MOVING W-NW AT 10-15
KT. THE LAST FEW VISIBLE SATELLITE IMAGES OF THE DAY SHOW AN
INVERTED-V STRUCTURE WITH CYCLONIC FLOW ABOUT THE AXIS IN THE
LOW-LEVEL CLOUD PATTERN. TOTAL PRECIPITABLE WATER IMAGERY ALSO
INDICATES A NORTHWARD EXTENSION OF LOW-LEVEL MOISTURE TO 11N IN
THE VICINITY OF THE WAVE AXIS. HOWEVER...DRY NW FLOW IN THE
MIDDLE TO UPPER LEVELS ABOVE THE LOW-LEVEL WAVE SIGNATURE IS
INHIBITING ANY SIGNIFICANT CONVECTION WITH THE WAVE THIS EVENING.

TROPICAL WAVE IS FROM 04N TO 12N ALONG 60W SE OF THE WINDWARD
ISLANDS AND TRINIDAD AND TOBAGO MOVING W-NW AT 10-15 KT. TOTAL
PRECIPITABLE WATER IMAGERY SHOWS DEEPER MOISTURE IN THE VERTICAL
AND A MORE DIFFLUENT ATMOSPHERE ALOFT THAN THE PREVIOUSLY
MENTIONED WAVE WHICH IS RESULTING IN SCATTERED SHOWERS AND
ISOLATED MODERATE CONVECTION FROM 05N-11N BETWEEN 57W-63W.

...ITCZ...

ITCZ AXIS IS ALONG 09N13W 03N35W 04N50W. SCATTERED MODERATE
CONVECTION IS WITHIN 120 NM NORTH OF THE AXIS BETWEEN 16W-27W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES A VERY DRY AIRMASS IS ASSOCIATED
WITH A MIDDLE TO UPPER LEVEL TROUGH POSITIONED ACROSS THE GULF
THIS EVENING. THE UPPER LEVEL TROUGH AXIS EXTENDS FROM NORTHERN
FLORIDA NEAR 29N82W TO NORTH OF THE YUCATAN PENINSULA NEAR
22N90W AND SUPPORTS A STATIONARY FRONT EXTENDING ACROSS THE
WESTERN FLORIDA PANHANDLE AND GULF COASTAL PLAIN ALONG 30N
BETWEEN 87W-92W. THE FRONT HAS INITIATED A FEW ISOLATED SHOWERS
IN THE VICINITY OF THE FLORIDA BIG BEND REGION HOWEVER THE LACK
OF SURFACE FORCING AND DRY AIR ALOFT IS ACTING QUICKLY TO
DIMINISH THE ACTIVITY. THE REMAINDER OF THE FLORIDA PENINSULA IS
EXPERIENCING ISOLATED SHOWERS AND TSTMS N OF 26N DUE TO
SEABREEZE INTERACTION AND PEAK DAYTIME HEATING. AREAL COVERAGE
OF THIS ACTIVITY SHOULD BEGIN TO WANE OVER THE NEXT 3 TO 6 HOURS
WITH LOSS OF MAXIMUM INSTABILITY. ELSEWHERE...THE REMAINDER OF
THE GULF WATERS REMAIN NEARLY CLOUDLESS WITH FAIR CONDITIONS AS
A SURFACE RIDGE ANCHORED BY A 1014 MB HIGH CENTERED NEAR 27N87W
RETAINS HOLD OVER AN OVERALL STABLE ATMOSPHERE. LASTLY...WHILE
SKIES REMAIN CLEAR...THE LAST FEW VISIBLE SATELLITE IMAGES OF
THE DAY INDICATE A HAZY ATMOSPHERE W OF 90W DUE TO THE ADVECTION
OF SMOKE FROM SOUTHERN MEXICO WILDFIRES. VISIBILITIES BELOW 10
STATUTE MILES...OR 8.7 NM ARE PREVALENT IN OBSERVATIONS ACROSS
THE SW GULF WATERS AND ALONG THE MEXICO GULF COAST S OF 26N.

CARIBBEAN SEA...
ZONAL WESTERLY FLOW ALOFT IS NOTED ACROSS MUCH OF THE CARIBBEAN
SEA THIS EVENING AS MOSTLY DRY AIR IS EVIDENT ON WATER VAPOR
IMAGERY N OF 17N W OF 70W. FAIR CONDITIONS AND RELATIVELY CLEAR
SKIES PREVAIL OVER MUCH OF THE NW CARIBBEAN WHILE ISOLATED
SHOWERS AND TSTMS IN ASSOCIATION WITH PEAK DAYTIME HEATING AND
INSTABILITY CONTINUE ACROSS INTERIOR PORTIONS OF CUBA AND
HISPANIOLA...AS WELL AS IN THE VICINITY OF JAMAICA. THIS
ACTIVITY IS EXPECTED TO DIMINISH OVER THE NEXT 3 TO 6 HOURS.
ELSEWHERE...CONVERGENT TRADEWIND FLOW IN THE LOW-LEVEL ALONG
WITH UPPER LEVEL DIFFLUENCE EAST OF AN UPPER LEVEL TROUGH AXIS
SKIRTING ACROSS SOUTHERN MEXICO IS GENERATING WIDELY SCATTERED
SHOWERS AND TSTMS OVER THE SW CARIBBEAN S OF 16N AND W OF A LINE
FROM 16N83W TO NORTHERN COLOMBIA NEAR 12N73W. THIS CONVECTION
REMAINS ENHANCED OVER INTERIOR PORTIONS OF GUATEMALA...
HONDURAS...EL SALVADOR...AND NORTHERN NICARAGUA DUE TO THE CLOSE
PROXIMITY OF THE EASTERN PACIFIC OCEAN ITCZ AXIS.

ATLANTIC OCEAN...
A SURFACE RIDGE COVERS THE WESTERN ATLC W OF 65W KEEPING
CONDITIONS MOSTLY FAIR THIS EVENING. HOWEVER...A FEW ISOLATED
SHOWERS AND TSTMS OVER THE INTERIOR FLORIDA PENINSULA ARE
DRIFTING INTO THE COASTAL ZONES OFF OF THE EAST COAST N OF 26N.
FARTHER EAST...A BROAD UPPER LEVEL LOW CONTINUES TO SPIN NEAR
32N51W SUPPORTING A PAIR OF 1015 MB SURFACE LOWS CENTERED NEAR
30N51W AND 30N57W. A SURFACE TROUGH EXTENDS FROM THE EASTERNMOST
LOW ALONG 27N52W 25N60W TO 24N65W SUPPORTING ISOLATED SHOWERS
WITHIN 90 NM EITHER SIDE OF THE SURFACE TROUGH AXIS. A SHEAR
LINE EXTENDS AROUND THE SYSTEM ALONG 32N48W 28N46W 23N49W TO
20N55W. SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS COVER A
VAST AREA FROM 18N-35N BETWEEN 38W-55W. THE PRESSURE GRADIENT
WITH THIS SYSTEM REMAINS STRONGEST IN THE NORTHEAST SEMICIRCLE
IN THE VICINITY OF 33N49W WITH GALE FORCE E-SE WINDS EXPECTED TO
CONTINUE OVER THE NEXT 24 HOURS. THE REMAINDER OF THE EASTERN
ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE EXTENDING
SOUTHWARD INTO THE DISCUSSION AREA ALONG 37W. FINALLY...AN
ELONGATED UPPER LEVEL LOW IS CENTERED NE OF THE MADEIRA ISLANDS
NEAR 35N15W. THIS DEEP LAYER TROUGH REFLECTS AS A 1011 MB LOW
CENTERED NEAR 33N15W WITH A SURFACE TROUGH EXTENDING FROM THE
LOW TO 28N21W.

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

$$
HUFFMAN




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