[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE MAR 15 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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.

...ITCZ...

ITCZ AXIS IS ANALYZED FROM 05N05W CROSSING THE EQUATOR NEAR 15W
TO 01S24W AND INTO NE BRAZIL NEAR 07S35W. SCATTERED MODERATE
CONVECTION IS FROM 01N-06N BETWEEN 13W-19W. SCATTERED MODERATE
AND ISOLATED STRONG CONVECTION IS FROM THE EQUATOR TO 02N
BETWEEN 21W-27W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES AN MIDDLE TO UPPER LEVEL LOW
CENTERED OVER THE OHIO RIVER VALLEY THIS EVENING WITH AN UPPER
LEVEL TROUGH AXIS EXTENDING SW ACROSS THE LOWER MISSISSIPPI
RIVER VALLEY AND EASTERN TEXAS NEAR 29N99W. THE ASSOCIATED COLD
FRONT AS OF 15/2100 UTC ENTERS THE NE GULF NEAR PENSACOLA
FLORIDA AND EXTENDS SW TO 28N90W WHERE IS BECOMES STATIONARY TO
THE TEXAS COAST NEAR 26N97W. LAST FEW VISIBLE SATELLITE IMAGES
OF THE DAY INDICATE THE FRONTAL BOUNDARY IS WEAKENING AND
BECOMING DIFFUSE WITH VERY LITTLE ISOLATED SHOWER ACTIVITY
REMAINING ALONG THE FRONT. A PRE-FRONTAL SURFACE TROUGH IS
ANALYZED FROM 30N86W TO 26N88W WITH ISOLATED SHOWERS OCCURRING
WITHIN 60 NM EAST OF THE BOUNDARY THIS EVENING. THE FRONT IS
FORECAST TO WEAKEN OVER THE NE GULF WITHIN THE NEXT 24 HOURS.
THE REMAINDER OF THE GULF THIS EVENING SE OF THE COLD FRONT IS
EXPERIENCING RELATIVELY LIGHT EASTERLY WINDS. AS THE CURRENT
FRONTAL BOUNDARY EXITS NE OF THE REGION BY EARLY WEDNESDAY...
SURFACE HIGH PRESSURE IS EXPECTED TO BUILD BACK IN ACROSS THE
GULF AND SE CONUS THROUGH THE REMAINDER OF THE WEEK.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED EAST OF THE
LEEWARD ISLANDS NEAR 12N44W THAT EXTENDS AN UPPER LEVEL RIDGE
AXIS WESTWARD TO 17N76W WHICH IS PROVIDING THE CARIBBEAN SEA
BASIN WITH DRY AIR AND MODERATE SUBSIDENCE ALOFT THIS EVENING.
AT THE SURFACE...MODERATE TO FRESH E-NE TRADES ARE EXPECTED TO
PREVAIL THROUGH FRIDAY WITH GLOBAL MODEL GUIDANCE INDICATING THE
TRADES WILL GRADUALLY INCREASE THROUGH THE WEEKEND DUE TO
STRONGER HIGH PRESSURE SETTLING INTO THE SW NORTH ATLC LATE
FRIDAY INTO EARLY SATURDAY. TOTAL PRECIPITABLE WATER IMAGERY
THIS EVENING INDICATES HIGHER VALUES OF LOW-LEVEL MOISTURE IN
THE ATMOSPHERE MOSTLY ACROSS PORTIONS OF THE NW CARIBBEAN S OF
20N W OF 83W...AND AN AREA OVER THE SOUTH-CENTRAL CARIBBEAN S OF
16N BETWEEN 71W-76W. ISOLATED SHOWERS ACCOMPANY THESE AREAS AND
WILL ARE EXPECTED TO CONTINUE MOVING WESTWARD THROUGH THE
OVERNIGHT HOURS.

ATLANTIC OCEAN...
MOSTLY WESTERLY ZONAL FLOW ALOFT IS LOCATED OVER THE SW NORTH
ATLC W OF 55W. THIS FAIRLY BENIGN UPPER LEVEL PATTERN IS
SUPPORTIVE OF A 1027 MB SURFACE HIGH CENTERED NEAR 30N70W WHICH
IS PROVIDING MUCH OF THE REGION W OF 60W WITH FAIR CONDITIONS
THIS EVENING. FARTHER EAST...A DISSIPATING STATIONARY FRONT
ENTERS THE DISCUSSION AREA NEAR 32N53W AND EXTENDS SW ALONG
30N57W TO 27N59W. ISOLATED SHOWERS ARE OCCURRING WITHIN 75 NM
EITHER SIDE OF THE BOUNDARY. SOUTH OF THIS DISSIPATING BOUNDARY
A WEAK 1017 MB LOW IS CENTERED NEAR 24N58W. A SURFACE TROUGH
EXTENDS FROM THE LOW TO 26N56W WITH ISOLATED SHOWERS WITHIN 60
NM OF THE SURFACE TROUGH. ANOTHER SURFACE TROUGH IS ANALYZED
EAST OF THE LOW FROM 22N48W TO 26N53W. THIS BOUNDARY LIKELY
CURLS INTO THE AFOREMENTIONED LOW HOWEVER...THE STRONGER WIND
FIELD OF 20 TO 25 KT E-SE WINDS REMAINS APPROXIMATELY 180 NM NE
OF THE BOUNDARY AS CAPTURED BY AN EARLIER MORNING ASCAT PASS.
ISOLATED SHOWERS ARE ALSO OCCURRING NE OF THE BOUNDARY FROM
21N-28N BETWEEN 44W-50W. THE REMAINDER OF THE CENTRAL AND
EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED
BY A 1027 MB HIGH CENTERED NEAR 33N30W.

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

$$
HUFFMAN




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