[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED 10 NOV 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND 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...
A BROAD LOW PRESSURE SYSTEM CENTERED ABOUT 300 MILES SOUTHWEST OF
PUERTO RICO IS PRODUCING WIDESPREAD CLOUDINESS AND THUNDERSTORMS
IN THE CENTRAL AND EASTERN CARIBBEAN SEA. UPPER-LEVEL WINDS ARE
ONLY MARGINALLY FAVORABLE FOR A TROPICAL OR SUBTROPICAL CYCLONE
TO DEVELOP DURING THE NEXT DAY OR TWO AS THE SYSTEM MOVES SLOWLY
NORTHEASTWARD. THE AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT
ORIGINALLY SCHEDULED FOR THIS AFTERNOON HAS BEEN CANCELED.
ANOTHER AIRCRAFT IS SCHEDULED TO INVESTIGATE THE SYSTEM THURSDAY
...IF NECESSARY. THE SYSTEM SHOULD PRODUCE HEAVY RAINFALL...
POSSIBLY CAUSING LIFE-THREATENING FLOODING AND MUD SLIDES...
IN PUERTO RICO...THE VIRGIN ISLANDS...AND THE NORTHERN AND
CENTRAL LESSER ANTILLES DURING THE NEXT COUPLE OF DAYS...EVEN
IF A TROPICAL CYCLONE DOES NOT DEVELOP. INTERESTS IN THE CENTRAL
AND EASTERN CARIBBEAN SEA SHOULD CLOSELY MONITOR THE PROGRESS OF
THIS SYSTEM. ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE FOUND
IN HIGH SEAS FORECASTS ISSUED BY THE TROPICAL ANALYSIS AND
FORECAST BRANCH... UNDER AWIPS HEADER HSFAT2 AND UNDER WMO
HEADER FZNT02 KNHC. SHOWERS AND THUNDERSTORMS FROM 9.5N AT THE
COLOMBIA BORDER TO 13N IN THE CARIBBEAN SEA BETWEEN 74W AND 76W
ARE ASSOCIATED WITH A MIDDLE LEVEL SHORTWAVE TROUGH ABOUT 100 NM
NORTH OF THE COLOMBIA COAST NEAR 9N76W. THIS SHORTWAVE IS
FORECAST TO MOVE NORTHEASTWARD DURING THE NEXT TWENTY FOUR
HOURS...AND CATCH UP TO THE SURFACE 1009 MB LOW PRESSURE CENTER
NEAR 15N70W. THIS SURFACE CENTER WILL BE QUASI-STATIONARY.
IT IS EXPECTED THAT THIS MIDDLE LEVEL SHORTWAVE WILL ENHANCE
THE CLOUDS AND PRECIPITATION IN THE VICINITY OF THE SURFACE
LOW CENTER. IT IS EXPECTED ALSO THAT THE WHOLE AREA OF DEEP
LAYER LOW PRESSURE AND PRECIPITATION SHOULD MOVE
EAST-NORTHEASTWARD DURING THE FOLLOWING 24 TO 48 HOURS AFTER
THE MIDDLE LEVEL SHORTWAVE AND THE SURFACE LOW CENTER BECOME
VERTICALLY ALIGNED. BROKEN TO OVERCAST MULTILAYERED CLOUDS
ARE EAST AND SOUTHEAST OF 20N71W 15N78W 11N83W...IN UPPER
LEVEL SOUTHWESTERLY WIND FLOW.

...TROPICAL WAVES...

CARIBBEAN SEA TROPICAL WAVE ALONG 73W/74W SOUTH OF 18N MOVING
WEST 10 TO 15 KT. UPPER LEVEL SOUTHWESTERLY FLOW IS ON TOP OF
THE WAVE. SHOWERS AND THUNDERSTORMS NORTH OF THE COLOMBIA COAST
ARE RELATED TO THE MIDDLE LEVEL SHORTWAVE TROUGH IN THAT AREA.

...ITCZ...

ITCZ 8N10W 8N20W 6N30W 6N40W 7N50W 9N60W 13N70W 11N80W 10N84W.
WIDELY SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND
THUNDERSTORMS FROM 4N TO 10N BETWEEN 15W AND 28W...AND FROM
1N TO 4N BETWEEN 35W AND 38W. THE ITCZ EAST OF 30W IS BEING
INFLUENCED BY DEEP LAYER CYCLONIC FLOW...NORTH OF 5N BETWEEN
20W AND 60W...AROUND AN EASTERN ATLANTIC CYCLONIC CIRCULATION
CENTER NEAR 27N32W. THE CLOUD TOPS OF SOME SHOWERS AND POSSIBLE
THUNDERSTORMS FROM 8N TO 11N BETWEEN 15W AND 30W ARE BEING
SHEARED BY THE UPPER LEVEL FLOW.

...DISCUSSION...

THE GULF OF MEXICO...
MIDDLE TO UPPER LEVEL CYCLONIC FLOW...WITH ONE TROUGH AFTER
ANOTHER ONE...ALONG 30N BETWEEN AT LEAST 100W AND 120W...FROM
TEXAS TO BAJA CALIFORNIA. UPPER LEVEL WESTERLY FLOW IS MOVING
ACROSS INTERIOR MEXICO FROM 20N TO 30N. UPPER LEVEL MOISTURE
ALSO HAS SPREAD EASTWARD...COVERING THE GULF WATERS NORTH OF
20N WEST OF 28N83W 22N86W. UPPER LEVEL WESTERLY FLOW PUSHING
THIS MOISTURE EASTWARD PRETTY MUCH IS WEST OF THIS 28N83W
22N86W LINE ALSO. MIDDLE LEVEL FLOW IS NORTHWESTERLY IN
THE REST OF THE GULF OF MEXICO. SURFACE COLD FRONT THROUGH
32N55W TO 26N60W 23N70W 23N80W 26N88W. DISSIPATING COLD FRONT
26N88W TO THE SOUTH CENTRAL LOUISIANA COAST NEAR 30N92W.
NO DEEP LAYER PRECIPITATION WITH THIS FRONT.

THE CARIBBEAN SEA...
DEEP LAYER TROUGH THROUGH 33N60W TO 20N70W AT THE NORTHERN EDGE
OF HISPANIOLA...TO THE CENTRAL NICARAGUA COAST. MIDDLE TO UPPER
LEVEL DRY AIR IS WEST OF A LINE THROUGH 32N58W 23N66W 16N77W
11N83W. SURFACE 1009 MB LOW PRESSURE CENTER NEAR 15N70W...IS THE
MAIN WEATHER FEATURE ON THE 10/1200 UTC SURFACE MAP. IT IS THE
SUBJECT OF THE SPECIAL FEATURE SECTION AT THE BEGINNING OF THIS
BULLETIN. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND SHOWERS AND
THUNDERSTORMS STRETCH FROM COSTA RICA TO HISPANIOLA. A SURFACE
TROUGH RUNS FROM 23N61W TO 17N65W TO THE 15N70W SURFACE LOW
CENTER.

THE SUBTROPICAL AND TROPICAL ATLANTIC WEST OF 40W...
DEEP LAYER TROUGH THROUGH 33N60W TO 20N70W AT THE NORTHERN EDGE
OF HISPANIOLA...TO THE CENTRAL NICARAGUA COAST. MIDDLE TO UPPER
LEVEL DRY AIR IS WEST OF A LINE THROUGH 32N58W 23N66W 16N77W
11N83W. SURFACE COLD FRONT THROUGH 32N55W TO 26N60W 23N70W 23N80W
26N88W. DISSIPATING COLD FRONT 26N88W TO THE SOUTH CENTRAL
LOUISIANA COAST NEAR 30N92W. NO DEEP LAYER PRECIPITATION WITH
THIS FRONT.

THE SUBTROPICAL AND TROPICAL ATLANTIC EAST OF 40W...DEEP LAYER
CYCLONIC FLOW...NORTH OF THE EQUATOR BETWEEN 20W AND 60W...
AROUND AN EASTERN ATLANTIC CYCLONIC CIRCULATION CENTER NEAR
29N29W. THE SURFACE 1004 MB LOW PRESSURE CENTER IS NEAR 29N30W.
A WARM FRONT GOES FROM THE LOW CENTER EASTWARD TO 30N20W 30N13W.
A TROUGH TRAILS THE 29N30W SURFACE LOW CENTER TO 26N30W 20N36W
AND 16N44W. UPPER LEVEL ANTICYCLONIC FLOW WITH A RIDGE COVERS
AFRICA AND ADJACENT ATLANTIC WATERS EAST OF 20W. BROKEN TO
OVERCAST MULTILAYERED CLOUDS AND RAIN ARE SPREADING EASTWARD
INTO AFRICA FROM 10N TO MOROCCO NEAR 32N...EAST OF 26N16W
16N33W. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS
WITHIN 30 TO 50 NM ON EITHER SIDE OF 31N25W 31N29W 29N33W.

$$
MT


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