[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 292354
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON JUN 28 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC...

...SPECIAL FEATURES...

TROPICAL STORM ALEX IS CENTERED NEAR 23.2N 94.5W AT 30/0000 UTC
MOVING WNW NEAR 11 KT. MINIMUM CENTRAL PRESSURE IS 980 MB WITH
MAXIMUM SUSTAINED WIND OF 60 KT WITH GUSTS TO 75 KT. TROPICAL
STORM AND HURRICANE WATCHES ARE IN EFFECT FOR PORTIONS OF NE
MEXICO AND SE TEXAS. THIS SYSTEM CONTINUES TO DRAW A
SIGNIFICANT AMOUNT OF DEEP LAYER MOISTURE ACROSS THE GULF OF
MEXICO AND NW CARIBBEAN GENERATING NUMEROUS STRONG CONVECTION
ACROSS THE YUCATAN PENINSULA FROM 18N-25N BETWEEN 88W-91W...NEAR
THE CENTER FROM 21N-24N BETWEEN 92W-96W...AND JUST OFF THE COAST
OF TEXAS AND LOUISIANA FROM 26N-29N BETWEEN 91W-96W. SCATTERED
STRONG CONVECTION IS ALSO FROM 17N-21N BETWEEN 91W-97W....AND
FROM 23N-26N BETWEEN 89W-99W. DUE TO THE LARGE AMOUNT OF
RAINFALL ACCUMULATED OVER THE PAST FEW DAYS OVER THESE
AREA...THE THREAT FOR FLASH FLOODING AND MUDSLIDES IS STILL HIGH
ON AREAS WHERE THE TERRAIN HAS BECOME SATURATED ESPECIALLY OVER
THE YUCATAN PENINSULA AND SE MEXICO. AS THE OUTER RAINBANDS
AFFECT SRN TEXAS AND NE MEXICO THE POTENTIAL FOR FLASH FLOODS
WILL INCREASE FOR THESE AREAS. ALEX IS EXPECTED TO CONTINUE TO
INTENSIFY AND SLOWLY TURN WNW AND DECREASE ITS FORWARD MOTION AS
IT APPROACHES THE NE MEXICO/SE TEXAS COAST. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS APPROACHING THE CAPE VERDE ISLANDS ALONG 18N21W
TO 5N23W MOVING W 15-20 KT. THE WAVE LIES AHEAD OF A DEEP LAYER
MOISTURE MAXIMUM EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY.
LOW-LEVEL CYCLONIC CURVATURE IS ALSO SEEN IN SATELLITE IMAGERY.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-9N
BETWEEN 21W-26W.

TROPICAL WAVE EXTENDS FROM 10N49W TO 4N46W MOVING W 10-15 KT.
LOW-LEVEL CYCLONIC FLOW IS ABOUT THE WAVE AXIS. THE WAVE ALSO
COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE EVIDENT IN TOTAL
PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM EQ-7N BETWEEN 43W-50W. A SURFACE TROUGH TO
THE NE OF THE WAVE ALONG 23N53W TO 12N59W MAY ORIGINATE FROM A
SPLIT PIECE OF ENERGY FROM THE WAVE AFTER INTERACTION WITH A
MID-LATITUDE FEATURE. THIS TROUGH MAY END UP BECOMING THE MORE
DOMINATE FEATURE AS THEY BOTH PROGRESS WWD.

TROPICAL WAVE EXTENDS ACROSS NICARAGUA FROM 16N84W TO 7N87W.
MOVING W NEAR 10 KT. WAVE IS FOLLOWING A DEEP LAYER MOISTURE
MAXIMUM EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY SEEN ACROSS
THE NW CARIBBEAN THAT IS BEING DRAWN INTO THE CIRCULATION OF
TROPICAL STORM ALEX. WHILE SOME OF THE ENERGY ASSOCIATED WITH
THE WAVE WILL MOST LIKELY BE ABSORBED INTO THIS SYSTEM...MODEL
DATA DOES INDICATE SOME PERTURBATION CONTINUING WWD INTO THE E
PACIFIC. SCATTERED STRONG CONVECTION IS WITHIN 30 NM EITHER SIDE
OF THE AXIS FROM 9N-12N.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N13W 9N23W 4N36W 6N48W 5N57W.
A LARGE AREA OF NUMEROUS STRONG CONVECTION IS MOVING OFF THE
COAST OF AFRICA FROM 8N-17N BETWEEN 10W-18W. ISOLATED
MODERATE/STRONG CONVECTION IS FROM 3N-7N BETWEEN 32W-34W.
SIMILAR ACTIVITY IS ALONG THE AXIS BETWEEN 39W-43W. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 2N-6N BETWEEN 53W-58W.

...DISCUSSION...

GULF OF MEXICO...
SIGNIFICANT MOISTURE ASSOCIATED WITH TROPICAL STORM ALEX IS
BEING DRAWN ACROSS THE ENTIRE GULF OF MEXICO SUPPORTING AREAS OF
SHOWERS/THUNDERSTORMS ACROSS THE MAJORITY OF THE BASIN. ALEX IS
CURRENTLY PRODUCING NUMEROUS STRONG CONVECTION
ACROSS THE YUCATAN PENINSULA FROM 18N-25N BETWEEN 88W-91W...NEAR
THE CENTER FROM 21N-24N BETWEEN 92W-96W...AND JUST OFF THE COAST
OF TEXAS AND LOUISIANA FROM 26N-29N BETWEEN 91W-96W. SCATTERED
STRONG CONVECTION IS ALSO FROM 17N-21N BETWEEN 91W-97W....AND
FROM 23N-26N BETWEEN 89W-99W. RADAR IMAGERY ALSO INDICATES
SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE ERN GULF OF MEXICO
AFFECTING THE NE GULF STATES INCLUDING THE FLORIDA PENINSULA.
SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS ON ALEX.
ALOFT...NW-NLY FLOW COVERS THE AREA E OF ALEX. EXPECT CONTINUED
SHOWER/THUNDERSTORM ACTIVITY ACROSS MUCH OF THE BASIN AS
MOISTURE WITH ALEX REMAINS ACROSS THE AREA. FOR MORE INFORMATION
AND UPDATES REGARDING ALEX...VISIT OUR WEBPAGE AT
WWW.NHC.NOAA.GOV.

CARIBBEAN SEA...
MOISTURE ASSOCIATED WITH TROPICAL STORM ALEX...AND A TROPICAL
WAVE FROM ACROSS NICARAGUA CONTINUES TO AFFECT THE NW CARIBBEAN
SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS W OF 75W INCLUDING
MUCH OF CUBA. SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE SW
CARIBBEAN S OF 9N DUE TO SURFACE CONVERGENCE NEAR A PORTION OF
THE E PACIFIC ITCZ THAT EXTENDS ACROSS COSTA RICA...AND PANAMA
TO NRN COLOMBIA. ISOLATED SHOWERS/THUNDERSTORMS HAVE ALSO FLARED
UP OVER NRN HISPANIOLA AND PUERTO RICO MOST LIKELY ENHANCED BY
THE COMBINATION OF DAYTIME HEATING AND UPPER LEVEL SUPPORT FROM
AN UPPER LEVEL LOW SPINNING N OF THE BAHAMAS NEAR 26N74W. THE
REMAINDER OF THE CENTRAL AND ERN CARIBBEAN IS INFLUENCED BY DRY
AIR ALOFT AROUND AN UPPER LEVEL RIDGE CENTERED NEAR 16N62W
KEEPING CONDITIONS FAIR. EXPECT MOISTURE AND WINDY CONDITIONS TO
REMAIN ACROSS THE NW CARIBBEAN INFLUENCED BY TROPICAL STORM
ALEX. ALSO EXPECT SHOWER/THUNDERSTORM ACTIVITY TO INCREASE
ACROSS THE LESSER ANTILLES AS A SURFACE TROUGH E OF THE ISLANDS
MOVES WWD.

ATLANTIC OCEAN...
A SURFACE TROUGH IS N OF TURKS AND CAICOS FROM 30N71W TO 25N72W
SUPPORTED BY A MID-UPPER LEVEL LOW NEAR 26N74W. WIDELY ISOLATED
SHOWERS/THUNDERSTORMS ARE FROM 20N-31N BETWEEN 65W-76W. A SECOND
SURFACE TROUGH IS ALONG 62W FROM 24N-30N ENHANCING ISOLATED
SHOWERS WITHIN 90 NM EITHER SIDE OF THE AXIS. A THIRD...AND
LARGER...SURFACE TROUGH IS E OF THE LESSER ANTILLES ALONG 23N53W
TO 12N59W. THIS TROUGH MAY HAVE ORIGINATED FROM A SPLIT PIECE OF
ENERGY FROM A TROPICAL WAVE TO ITS SE. THE TROUGH PRECEDES AN
AREA OF ENHANCED MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER
IMAGERY. IT IS POSSIBLE THAT THIS TROUGH WILL GAIN DOMINANCE
OVER THE TROPICAL WAVE AS IT MOVES WWD WITH THE POTENTIAL TO
FLAIR UP SHOWERS/THUNDERSTORMS ACROSS THE LESSER ANTILLES AND NE
CARIBBEAN ISLANDS. ELSEWHERE ACROSS THE ATLANTIC...A BROAD
SURFACE RIDGE DOMINATES ANCHORED BY A 1030 MB AZORES HIGH NEAR
34N43W KEEPING CONDITIONS FAIR ACROSS THE BASIN. ALOFT...WATER
VAPOR IMAGERY INDICATES A DRY AND STABLE AIRMASS ACROSS THE ERN
HALF OF THE BASIN FURTHER SUPPORTING THE FAIR WEATHER. AN UPPER
LEVEL RIDGE EXTENDS BETWEEN 55W-68W WITH A CIRCULATION CENTER
NEAR 16N62W...AND 36N55W E OF THE AFOREMENTIONED UPPER LEVEL
LOW. A SECOND UPPER LEVEL TROUGH EXTENDS FROM 31N26W TO 23N55W.
AN UPPER LEVEL RIDGE CENTERED OVER NW AFRICA NEAR 20N16W COVERS
THE REMAINDER OF THE BASIN.

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

$$
WALTON





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