[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202355
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAY 20 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 IS ALONG 32W S OF 10N MOVING W AT 10-15 KT.
LOW-LEVEL CYCLONIC FLOW IS NOTED AT LOW LATITUDE...S OF 6N...AS
THE WAVE REMAINS EMBEDDED WITHIN THE ITCZ. WIDELY SCATTERED
MODERATE CONVECTION IS FROM THE EQUATOR TO 6N BETWEEN 29W-34W.

TROPICAL WAVE IS ALONG 52W S OF 11N MOVING W AT 10-15 KT. THE
WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE
AS NOTED IN TOTAL PRECIPITABLE WATER IMAGERY BETWEEN 48W-57W
WITH AN AREA OF SCATTERED MODERATE CONVECTION W OF THE WAVE AXIS
FROM 7N-10N BETWEEN 52W-59W.

TROPICAL WAVE IS ALONG 77W S OF 12N MOVING W AT 10-15 KT. THE
WAVE CONTINUES ENHANCING AFTERNOON CONVECTION OVER INLAND
COLOMBIA...EASTERN PANAMA...AND ADJACENT COASTAL WATERS S OF 12N
BETWEEN 73W-78W IN THE SW CARIBBEAN SEA.

TROPICAL WAVE IS ALONG 84W S OF 12N MOVING W AT 10 KT. WHILE
LARGELY LOCATED IN THE E PACIFIC REGION...SCATTERED MODERATE AND
ISOLATED STRONG CONVECTION IS S OF 13N W OF 80W...INCLUDING
INLAND PORTIONS OF WESTERN PANAMA...COSTA RICA...AND SOUTHERN
NICARAGUA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N14W 4N32W 5N41W 5N51W. SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF THE W
AFRICA COAST BETWEEN 10W-14W. ELSEWHERE...SCATTERED MODERATE
CONVECTION IS WITHIN 120 NM NORTH AND 300 NM SOUTH OF THE AXIS E
OF 30W. A SURFACE TROUGH IS ALONG 41W S OF 9N WITH NO
SIGNIFICANT DEEP CONVECTION ASSOCIATED WITH THIS FEATURE.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY THIS EVENING INDICATES VERY DRY AND STABLE
CONDITIONS ALOFT OVER MUCH OF THE GULF AND FLORIDA PENINSULA
WITH NEARLY ZONAL UPPER LEVEL WESTERLY FLOW FROM ACROSS MEXICO
TO 80W. THIS UPPER LEVEL REGIME IS CONTINUING TO SUPPORT A WEAK
SURFACE RIDGE GENERALLY E TO SE WINDS UP TO 15 KT. HOWEVER...
LOW-LEVEL MOISTURE IS ADVECTING FROM THE NW CARIBBEAN SEA AND
CUBA OVER THE SE GULF WATERS AND STRAITS OF FLORIDA PROVIDING
FOR ISOLATED SHOWERS S OF 25N E OF 88W. THIS ACTIVITY IS MOST
FOCUSED ALONG A SURFACE TROUGH ANALYZED FROM 24N85W THROUGH THE
YUCATAN CHANNEL TO A 1007 MB LOW CENTERED OFFSHORE OF THE
YUCATAN PENINSULA NEAR 19N87W. GLOBAL MODEL GUIDANCE SUGGESTS
THE LOW AND SURFACE TROUGH WILL DRIFT WESTWARD AROUND THE
SOUTHERN PERIPHERY OF THE RIDGE AND WEAKEN AS IT MOVES OVER THE
SW GULF THROUGH EARLY SUNDAY.

CARIBBEAN SEA...
A 1007 MB LOW IS CENTERED OFFSHORE OF THE YUCATAN PENINSULA NEAR
19N87W WITH A SURFACE TROUGH EXTENDING NE FROM THE LOW TO
WESTERN CUBA AND S-SW FROM THE LOW TO THE GULF OF HONDURAS.
SCATTERED SHOWERS AND TSTMS ARE OCCURRING EAST OF THE SURFACE
TROUGH OVER THE NW CARIBBEAN FROM 17N-22N BETWEEN 77W-86W. THIS
CONVECTIVE ACTIVITY CONTINUES TO BE ENHANCED BY UPPER LEVEL
DIFFLUENCE ACROSS PORTIONS OF THE NW CARIBBEAN AND CUBA...
EXTENDING NE INTO THE W ATLC E OF 80W...ALL LOCATED EAST OF AN
UPPER LEVEL TROUGH AXIS ALONG 32N74W TO 20N82W. ISOLATED SHOWERS
AND TSTMS SPREAD FARTHER EAST...REMAINING LARGELY N OF 17N
ACROSS THE NORTHERN CARIBBEAN SEA AND GREATER ANTILLES THIS
EVENING DUE TO A BROAD AREA OF CONVERGENT TRADE WINDS. WITH THE
UPPER LEVEL TROUGH SLOW TO MOVE EASTWARD OVER THE NEXT COUPLE OF
DAYS AND ANTICIPATED CYCLOGENESIS TO OCCUR OVER THE W ATLC ALONG
70W OVER THE NEXT 24-36 HOURS...CONTINUED PRECIPITATION IS
FORECAST ACROSS PORTIONS OF HISPANIOLA AND CUBA THROUGH THE
WEEKEND. ELSEWHERE...A PAIR OF TROPICAL WAVES ARE PROGRESSING
WESTWARD ACROSS THE SW CARIBBEAN BRINGING SCATTERED SHOWERS AND
ISOLATED TSTMS S OF 13N BETWEEN 75W-87W...INCLUDING INLAND
SECTIONS OF CENTRAL AMERICA THIS EVENING.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS ACROSS THE W ATLC WITH AXIS ALONG
32N74W TO WESTERN CUBA NEAR 22N80W. THE LAST FEW VISIBLE
SATELLITE IMAGES OF THE DAY INDICATE THE UPPER LEVEL TROUGH IS
INDUCING CYCLOGENESIS NE OF THE BAHAMAS WITH A 1014 MB LOW
CENTERED NEAR 25N75W. A SURFACE TROUGH EXTENDS ALONG 75W THROUGH
THE LOW FROM 22N-28N. SCATTERED SHOWERS AND ISOLATED TSTMS ARE
OCCURRING OVER A LARGE PORTION OF THE W ATLC DUE TO THE SURFACE
FEATURE AS WELL AS AN UPPER LEVEL DIFFLUENT PATTERN FROM 19N-32N
BETWEEN 60W AND THE UPPER LEVEL TROUGH AXIS. THIS AREA OF LOW
PRESSURE IS FORECAST TO FURTHER DEVELOP AS IT MOVES E-NE OVER
THE NEXT 24-48 HOURS. A STATIONARY FRONTAL BOUNDARY IS LOCATED
TO THE NW...ANALYZED FROM 32N74W TO NEAR JACKSONVILLE FLORIDA
WITH ONLY ISOLATED SHOWERS OCCURRING WITHIN 30 NM OF THE FRONT.
THIS FRONT IS LARGELY SUPPORTED BY THE UPPER LEVEL TROUGH AND IS
FORECAST TO BECOME DIFFUSE BY LATE FRIDAY. A BROAD SURFACE RIDGE
ENGULFS THE REMAINDER OF THE ATLC E OF 70W ANCHORED BY A 1031 MB
HIGH CENTERED NORTH OF THE DISCUSSION AREA NEAR 37N45W.
HOWEVER...TWO SURFACE TROUGHS ARE LOCATED OVER THE TROPICAL
NORTH AND SW NORTH ATLC AREA. THE FIRST SURFACE TROUGH IS
ANALYZED FROM 18N50W TO 13N53W WITH ISOLATED SHOWERS FROM
14N-19N BETWEEN 48W-55W. THE SECOND SURFACE TROUGH IS NORTH OF
THE LEEWARD ISLANDS FROM 17N-23N ALONG 62W. ISOLATED SHOWERS ARE
LOCATED WITHIN 200 NM OF THE TROUGH AXIS. A COLD FRONT ALSO
SKIRTS THE NORTHERN FRINGE OF THE DISCUSSION AREA ENTERING THE
EASTERN ATLC NEAR 32N31W SW TO 30N37W. ISOLATED SHOWERS ARE
WITHIN 60 NM OF THE FRONT.

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

$$
HUFFMAN



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