[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011809 AAA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE AUG 01 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURE...

TROPICAL STORM CHRIS IS APPROACHING THE NORTHERNMOST LEEWARD
ISLANDS. THE CENTER OF T.S. CHRIS IS LOCATED NEAR 17.6
NORTH...LONGITUDE 60.9 WEST OR ABOUT 65 MILES...EAST-NORTHEAST
OF ANTIGUA AT 01/1800 UTC. CHRIS IS MOVING TOWARD THE
WEST-NORTHWEST NEAR 10 KT. ON THE FORECAST TRACK...CHRIS IS
EXPECTED TO MOVE NEAR OR OVER THE NORTHERNMOST LEEWARD ISLANDS
LATER TODAY AND TONIGHT. THE ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1009MB. THE MAXIMUM SUSTAINED WINDS ARE 35 KT WITH HIGHER
GUSTS. PLEASE REFER TO THE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT3/ WTNT23 KNHC AND THE PUBLIC ADVISORY
MIATCPAT3/WTNT33 KNHC FOR MORE DETAILS. SCATTERED MODERATE
CONVECTION ASSOCIATED WITH CHRIS LIES FROM 14N TO 20N BETWEEN
56W AND 63W...PRODUCING STRONG SHOWERS AND THUNDERSTORMS IN THE
AREA. RAINFALL AMOUNTS OF 3 TO 5 INCHES WITH ISOLATED HIGHER
AMOUNTS TO NEAR 8 INCHES ARE POSSIBLE OVER THE NORTHERN LEEWARD
ISLANDS IN ASSOCIATION WITH CHRIS. NORTHERLY SHEAR IS CURRENTLY
IMPACTING CHRIS IN ASSOCIATION WITH AN UPPER LEVEL LOW TO ITS
NNE...AND AN UPPER RIDGE TO THE WEST CENTERED JUST SOUTH OF
CUBA. THIS HAS LED TO SOME SLIGHT WARMING OF THE CLOUD TOPS IN
THE CONVECTIVE ACTIVITY IN THE NE AND SW QUADRANTS...AND IS
INHIBITING OUTFLOW IN THE NW QUADRANT. HOWEVER...CHRIS COULD
MOVE INTO A LOW SHEAR ENVIRONMENT BETWEEN TWO UPPER LOWS OVER
THE NEXT SEVERAL DAYS WHICH WOULD BE MORE FAVORABLE FOR
STRENGTHENING.

...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE ERN ATLC ALONG 29W/30W S OF 18N MOVING
W 15 TO 20 KT. THIS WAVE EXHIBITS BROAD CYCLONIC CURVATURE WITH
AN INVERTED V SHAPE. SCATTERED MODERATE CONVECTION ASSOCIATED
WITH THIS WAVE IS MIXED WITH ITCZ SHOWERS AND THUNDERSTORMS FROM
2N TO 16N BETWEEN 23W AND 37W.

A TROPICAL WAVE IS LOCATED IN THE CARIBBEAN SEA ALONG 69W/70W S
OF 15N MOVING W 15 KT. THIS WAVE HAS BEEN DIFFICULT TO
DISTINGUISH TODAY AS IT INTERACTS WITH BROAD UPPER LEVEL
EASTERLY FLOW ALONG WITH THE LOW LEVEL CYCLONIC FLOW AROUND THE
TYPICAL SURFACE LOW OVER NORTHERN COLOMBIA. THERE IS A SMALL
AREA OF MODERATE CONVECTION WEST OF THIS WAVE NEAR 10N72W BUT
OVERALL THERE IS VERY LITTLE SIGNIFICANT CONVECTION ASSOCIATED
WITH THE WAVE. THIS IS THE SOUTHERN PORTION OF THE WAVE THAT
SPLIT YESTERDAY JUST EAST OF THE LESSER ANTILLES...WITH THE
NORTHERN PORTION NOW T.S. CHRIS.

A TROPICAL WAVE IS BEGINNING TO MOVE OUT OF THE WESTERN
CARIBBEAN SEA ALONG 88W/89W S OF 21N. THIS WAVE WILL MOVE W 15
TO 20 KT THROUGH THE BAY OF CAMPECHE LATER TODAY AND TONIGHT. A
WEAK INVERTED V PATTERN IS NOTED WITH THIS WAVE. A PATCH OF
MODERATE CONVECTION IS NOTED NEAR THE WAVE AXIS IN THE VICINITY
OF COASTAL BELIZE AND GUATEMALA...WHICH MAY ALSO BE ASSOCIATED
WITH UPSLOPE E/SE FLOW ALONG THE NEARBY TERRAIN. CONVECTION
ELSEWHERE ALONG THE WAVE IS MINIMAL.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N12W 12N28W 10N31W 12N54W. EAST OF
THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE AND ITCZ ALONG
29W...ISOLATED MODERATE SHOWERS AND THUNDERSTORMS EXIST WITHIN
250NM ON EITHER SIDE OF THE AXIS. WEST OF THE CONVECTION
ASSOCIATED WITH THE WAVE ALONG 29W...MOSTLY MINIMAL SHOWER AND
THUNDERSTORM ACTIVITY IS NOTED THROUGH THE NE SOUTH AMERICAN
COAST.

...DISCUSSION...
THE GULF OF MEXICO...
WATER VAPOR IMAGERY SHOWS AN UPPER LOW EXTENDING ACROSS NE
MEXICO AND SOUTHERN TEXAS INTO THE NW GULF OF MEXICO. DISTINCT
ANTICYCLONIC FLOW IS NOTED SOUTH OF THIS AREA AROUND AN UPPER
HIGH CENTERED NEAR VERACRUZ MEXICO/SW BAY OF CAMPECHE. MOSTLY
ISOLATED SHOWER AND THUNDERSTORM ACTIVITY DOMINATES THE WESTERN
THIRD OF THE GULF. A SWATH OF DRY AIR/FAIR WEATHER LIES IN
THE CENTRAL AND EAST GULF FROM 23N TO 29N BETWEEN 82W AND 93W. A
SMALL PATCH OF MODERATE CONVECTION IN THE FAR NORTH CENTRAL
GULF...JUST SOUTH OF PANAMA CITY FLORIDA...SHOULD MOVE NORTH OUT
OF THE GULF OVER THE NEXT FEW HOURS AS IT ROTATES AROUND AN
UPPER LOW SEEN SPINNING IN SOUTHERN ALABAMA/MISSISSIPPI. THE
SURFACE PATTERN IN THE GULF REMAINS FAIRLY BENIGN AS A SURFACE
HIGH CENTERED OVER SOUTHERN GEORGIA ALONG WITH THE WESTERN
PORTION OF AN ATLC SURFACE HIGH IS PRODUCING 5 TO 15KT E/SE
WINDS OVER MUCH OF THE GULF. EVEN LIGHTER WINDS EXIST IN THE FAR
NE PORTION OF THE GULF/APALACHEE BAY CLOSER TO THE HIGH CENTER.
SIMILAR CONDITIONS EXPECTED THE NEXT COUPLE OF DAYS AS A FAIRLY
WEAK SURFACE ANTICYCLONE PATTERN DOMINATES.

THE CARIBBEAN SEA...
AN UPPER LEVEL HIGH PRESSURE AREA IS LOCATED IN THE NW CARIBBEAN
SEA...SOUTH OF CUBA...CENTERED NEAR 19N81W. ANOTHER UPPER HIGH
IS EXTENDING INTO THE FAR NW PORTION OF THE CARIBBEAN SEA FROM
ITS CENTER NEAR VERACRUZ MEXICO. ISOLATED SHOWERS AND
THUNDERSTORMS ARE NOTED IN THE NW CARIBBEAN IN WEAK UPPER
DIFFLUENCE OCCURRING BETWEEN THESE HIGHS FROM 14N TO 21N BETWEEN
77W AND 88W. A BROAD AREA OF EASTERLY FLOW IS NOTED S AND SE OF
THE UPPER HIGH SOUTH OF CUBA...THAT COVERS MUCH OF THE
CARIBBEAN. A NARROW SWATH OF WEAK TO MODERATE CONVECTION FROM
T.S. CHRIS IS SPREADING WSW FROM THE LESSER ANTILLES AND INTO
THE ERN CARIBBEAN SEA THIS AFTERNOON IN ASSOCIATED WITH THE
STRONG UPPER LEVEL ENE/NE FLOW OVER THE AREA. THE CENTER OF T.S
CHRIS IS EXPECTED TO REMAIN OUT OF THE CARIBBEAN SEA.
HOWEVER...STRONG SHOWERS AND THUNDERSTORMS ASSOCIATED WITH CHRIS
WILL LIKELY PRODUCE HEAVY RAINFALL OVER THE NORTHERN LESSER
ANTILLES AND LEEWARD ISLANDS TODAY AND TOMORROW. AT THE
SURFACE...10 TO 20KT E TO SE FLOW IS DOMINATING ON THE SW SIDE
OF THE ATLANTIC HIGH. QUIKSCAT DATA FROM THIS MORNING SHOWED
SLIGHTLY STRONGER 20 TO 25KT E WINDS IN THE CENTRAL CARIBBEAN
WATERS BETWEEN VENEZUELA/COLOMBIA AND HISPANIOLA. GFS SEEMS TO
HAVE INITIALIZED THIS SLIGHTLY STRONGER SFC WIND AREA WELL AND
SUGGESTS IT WILL PERSIST WHILE EXPANDING FURTHER WEST OVER THE
NEXT COUPLE OF DAYS...AS THE SW PORTION OF THE ATLANTIC HIGH
INTERACTS WITH THE COLOMBIAN LOW.

THE ATLANTIC OCEAN...
STRONG UPPER LEVEL NE WINDS EXIST IN THE ATLANTIC WATERS JUST
OFFSHORE NORTH AND CENTRAL FLORIDA THIS AFTERNOON IN RESPONSE TO
THE INTERACTION BETWEEN AN UPPER HIGH OVER THE CAROLINAS WITH AN
UPPER LOW CENTERED NEAR 25N71W JUST NE OF THE BAHAMAS AND TURKS
AND CAICOS ISLANDS. SCATTERED...HEAVILY SHEARED...SHOWERS AND
THUNDERSTORMS EXIST ON THE EAST SIDE OF THIS UPPER LOW IN THE
AREA BETWEEN COASTAL HISPANIOLA THROUGH THE E/W LINE FROM 27N65W
TO 27N72W. SURFACE WINDS IN THIS AREA SHOW CYCLONIC TURNING AND
SURFACE PRESSURES IN THE AREA SHOW SOME WEAK TROUGHING. THUS...A
WEAK REFLECTION OF THIS UPPER LOW IS ANALYZED AS A SURFACE TROF
ON THE 12Z MAP. LARGE SCALE UPPER RIDGING CONTINUES TO DOMINATE
MUCH OF THE CENTRAL AND EASTERN ATLC WATERS FROM ITS CENTER NEAR
21N33W. A LONGWAVE UPPER TROF IS LOCATED NW OF THIS RIDGE MOSTLY
N OF 30N BETWEEN 47W AND 63W. SURFACE HIGH PRESSURE IS
DOMINATING MUCH OF THE TROPICAL ATLANTIC WATERS ON THE SOUTH AND
WEST PORTION OF ITS 1030MB CENTER NEAR 36N24W. THE OTHER SURFACE
FEATURES NOTED ARE OBVIOUSLY T.S CHRIS NEARING THE LEEWARD
ISLANDS AND THE BROAD TROPICAL WAVE ALONG 30W...SEE MORE INFO ON
THESE FEATURES ABOVE.

$$
WILLIS



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