[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 172349
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE AUG 17 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.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 23N22W TO 09N29W MOVING W AT 10-15
KT. GLOBAL MODEL GUIDANCE AND POTENTIAL VORTICITY FIELDS
INDICATE THAT THE SOUTHERN EXTENT OF THE WAVE IS EMBEDDED WITHIN
A BROAD MONSOONAL TROUGH ACROSS THE TROPICAL ATLC S OF 16N
BETWEEN 21W-36W. THE WAVE ALSO COINCIDES WITH A MAXIMUM IN DEEP
LAYER MOISTURE INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY E
OF 31W. AFRICAN DUST IS NOTED BEHIND THE WAVE AXIS FROM 17N-28N.
DUE TO THIS AREA OF DRIER AIR...NO SIGNIFICANT AREAS OF DEEP
CONVECTION ARE CURRENTLY ASSOCIATED WITH THE WAVE.

TROPICAL WAVE EXTENDS FROM 23N34W TO 10N40W MOVING W AT 10-15
KT. BROAD LOW-LEVEL CYCLONIC FLOW IS NOTED IN THE VICINITY OF
THE WAVE WITH A LARGE SURGE OF DEEP LAYER MOISTURE LOCATED TO
THE EAST AND REMAINING LARGELY ASSOCIATED WITH THE PREVIOUS
TROPICAL WAVE. THE SIGNIFICANT DRY AIR TO THE EAST IS
SUPPRESSING CONVECTION NEAR THE WAVE AND LIMITING IT TO THE ITCZ
REGION S OF 11N.

TROPICAL WAVE IS FROM 11N-23N ALONG 71W MOVING W AT 15-20 KT.
BROAD LOW-LEVEL CYCLONIC FLOW IS IN THE VICINITY OF THE WAVE
AXIS AS IT MOVES ACROSS THE CENTRAL CARIBBEAN. TOTAL
PRECIPITABLE WATER VALUES ARE MAXIMIZED S OF 23N BETWEEN
62W-72W...WITH SCATTERED MODERATE AND ISOLATED STRONG CONVECTION
OCCURRING FROM 13N-23N BETWEEN 64W-75W...INCLUDING PUERTO RICO
AND HISPANIOLA.

TROPICAL WAVE IS FROM 09N-21N ALONG 88W MOVING W AT 10-15 KT.
THE WAVE LIES EMBEDDED WITH AN AREA OF MODERATE DEEP LAYER
MOISTURE AS INDICATED ON TOTAL PRECIPITABLE WATER IMAGERY
COVERING THE WESTERN CARIBBEAN SEA AND PORTIONS OF THE SOUTHERN
GULF OF MEXICO. THE WAVE IS ALSO COLLOCATED WITH AN UPPER LEVEL
TROUGH OVER THE NW CARIBBEAN PROVIDING DIFFLUENCE WEST OF THE
WAVE AXIS WHERE SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS OCCURRING FROM 18N-22N BETWEEN 86W-92W. SCATTERED
MODERATE CONVECTION IS ALSO LOCATED EAST OF THE WAVE AXIS
OCCURRING S OF 19N BETWEEN 84W-88W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 18N16W 12N39W 06N56W 08N63W. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 04N-12N BETWEEN 13W-46W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION COVERS MUCH OF THE
SE CONUS CENTERED OVER NORTHERN LOUISIANA AND IS PROVIDING THE
GULF WITH E-NE UPPER LEVEL FLOW. EMBEDDED BENEATH THIS UPPER
LEVEL RIDGE IS A 1010 MB SURFACE LOW...THE REMNANT OF T.D.
FIVE...CENTERED INLAND OVER EASTERN LOUISIANA NEAR 31N90W. A
SURFACE TROUGH EXTENDS SW FROM THE LOW ALONG 29N91W TO THE TEXAS
COAST NEAR 27N97W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE
GENERALLY REMAINING INLAND THIS EVENING OVER TEXAS AND
LOUISIANA...HOWEVER...ISOLATED SHOWERS ARE OCCURRING NW OF A
LINE FROM MOBILE BAY TO 26N92W TO THE MEXICO COAST NEAR 25N98W.
ANOTHER WEAKER SURFACE TROUGH IS LOCATED IN THE SW GULF AND IS
ANALYZED FROM 20N96W TO 23N97W. ISOLATED SHOWERS ARE S OF 23N W
OF 96W. WITH THE APPROACH OF A TROPICAL WAVE ALONG 88W...
INCREASED MID-LEVEL MOISTURE IS NOTED ON WATER VAPOR IMAGERY AND
IS PROVIDING FOR SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE
FLORIDA PENINSULA...EASTERN GULF...AND YUCATAN PENINSULA...
STRETCHING INTO PORTIONS OF THE EASTERN BAY OF CAMPECHE THIS
EVENING. THIS ACTIVITY LIES MAINLY EAST OF A LINE FROM THE
FLORIDA BIG BEND REGION NEAR 30N83W TO 25N91W TO 18N93W.

CARIBBEAN SEA...
A TROPICAL WAVE IS IMPACTING THE WESTERN CARIBBEAN AND PORTIONS
OF CENTRAL AMERICA EXTENDING ALONG 88W FROM NEAR CANCUN MEXICO
TO EASTERN EL SALVADOR AND INTO THE EASTERN PACIFIC. THE
TROPICAL WAVE ALONG WITH A SURFACE TROUGH ANALYZED TO THE SE
FROM 10N82W TO 15N83W ARE GENERATING SCATTERED SHOWERS AND TSTMS
SW OF A LINE FROM THE YUCATAN CHANNEL TO NORTHERN COLOMBIA NEAR
10N76W. THIS AREA...IN ADDITION TO MOST OF CENTRAL AMERICA...
FALLS BENEATH AN UPPER LEVEL TROUGH WITH AXIS ALONG 87W...WHICH
COLLOCATES WITH THE TROPICAL WAVE AXIS. THE STRONGEST CONVECTION
IS LOCATED IN THE VICINITY OF THE SURFACE TROUGH FROM 11N-15N
BETWEEN 78W-85W. FARTHER EAST...A SECOND TROPICAL WAVE IS
IMPACTING THE EASTERN AND CENTRAL CARIBBEAN EXTENDING FROM THE W
ATLC ACROSS CENTRAL HISPANIOLA TO ARUBA ALONG 71W. SCATTERED
SHOWERS AND TSTMS ARE OCCURRING OVER A LARGE AREA FROM 13N-23N
BETWEEN 64W-75W...INCLUDING PUERTO RICO AND HISPANIOLA. AS THE
TROPICAL WAVE ALONG 71W MOVES WESTWARD...CONDITIONS REMAIN FAIR
ACROSS THE LESSER ANTILLES AND THE EASTERN CARIBBEAN E OF 64W
THIS EVENING DUE TO DRY AIR ASSOCIATED WITH AN UPPER LEVEL LOW
CENTERED OVER THE TROPICAL N ATLC NEAR 18N52W.

ATLANTIC OCEAN...
A WEAK SURFACE TROUGH...REMNANTS OF A FRONTAL BOUNDARY...REMAIN
IN THE W ATLC ALONG 32N65W 30N70W 30N75W 29N78W. ISOLATED
SHOWERS AND TSTMS ARE WITHIN 120 NM EITHER SIDE OF THE TROUGH
AXIS. ALOFT...AN UPPER LEVEL RIDGE AXIS ALONG 33N TO 60W
CONTINUES TO PROVIDE NE TO E FLOW OVER THE W ATLC. A SLIGHT
WEAKNESS IN THIS UPPER LEVEL RIDGE OVER THE NW BAHAMAS AND
SOUTHERN FLORIDA PENINSULA IS SUPPORTING SCATTERED SHOWERS AND
ISOLATED TSTMS THIS EVENING FROM 23N-28N BETWEEN 75W-81W. A
TROPICAL WAVE S OF 23N ALONG 71W IS SUPPORTING SCATTERED SHOWERS
AND ISOLATED TSTMS OVER HISPANIOLA AND PUERTO RICO AND AREAS
NORTH OF THOSE ISLANDS FROM 18N-23N BETWEEN 66W-74W. FARTHER
EAST...A SURFACE RIDGE DOMINATES ANCHORED BY A 1029 MB HIGH
CENTERED OVER THE AZORES NEAR 40N27W. THE SURFACE RIDGE AXIS
EXTENDS SW TO A 1024 MB HIGH CENTERED NEAR 29N56W THEN WSW TO
26N74W. THE RIDGE IS MAINTAINING FAIR WEATHER OVER MUCH OF THE
CENTRAL AND EASTERN ATLC WITH THE SAHARAN AIR LAYER PROVIDING
OVERALL STABLE CONDITIONS N OF 12N BETWEEN 32W-60W. ALOFT...AN
UPPER LEVEL CYCLONE IS CENTERED E OF LESSER ANTILLES NEAR
18N52W. AN UPPER LEVEL ANTICYCLONE IS COVERING THE FAR E ATLC
CENTERED NEAR 26N29W.

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

$$
HUFFMAN



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