[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 281805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE JUN 28 2005

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 SURFACE TROUGH RUNS FROM THE NORTH CENTRAL GULF OF MEXICO NEAR
30N88W TO 26N93W INTO THE SOUTHWESTERN GULF OF MEXICO AND THE
ISTHMUS OF TEHUANTEPEC NEAR 18N95W. THIS TROUGH HAS BEEN MOVING
WESTWARD DURING THE LAST FEW DAYS...RUNNING FROM THE YUCATAN
PENINSULA TO THE SOUTHEASTERN GULF OF MEXICO EARLIER THIS WEEK.
A SURFACE LOW PRESSURE CENTER IS FORECAST TO DEVELOP IN THE
SOUTHWESTERN GULF OF MEXICO DURING THE NEXT 24 HOURS...POSSIBLY
BECOMING A TROPICAL CYCLONE. AN UPPER LEVEL RIDGE RUNS FROM THE
SOUTHWESTERN GULF OF MEXICO TO THE NORTHEASTERN GULF AND
EVENTUALLY NORTHEASTWARD EVEN MORE TOWARD NORTH CAROLINA.
A MIDDLE TO UPPER LEVEL SHEAR AXIS OR REALLY NARROW AND SHARP
TROUGH RUNS THROUGH 30N90W TO 25N94W AND 21N98W. MIDDLE TO UPPER
LEVEL DRY AIR IS NORTHWEST OF THIS 30N90W 21N98W LINE. UPPER
LEVEL ANTICYCLONIC FLOW IS WITHIN 210 NM ON EITHER SIDE OF THE
RIDGE. SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS
ARE FOUND NOW FROM 19N TO 21N BETWEEN 94W AND 96W...FROM 23N TO
26N BETWEEN 88W AND 92W...AND FROM 27N TO 29N BETWEEN 85W AND
87W. OTHER SHOWERS AND THUNDERSTORMS MAY UNDER THIS RIDGE ALSO.

...TROPICAL WAVES...

EASTERN ATLANTIC TROPICAL WAVE ALONG 18W SOUTH OF 15N MOVING
WEST 10 KT. WE HAVE BEEN FOLLOWING THIS WAVE VIA AFRICA
RAWINSONDE OBSERVATIONS DURING THE LAST 48 HOURS OR SO. IT IS
POSSIBLE THAT ITS MOVEMENT HAS PUSHED IT TO 20W/21W...BASED
ON SOME CYCLONIC FLOW APPARENT IN CURRENT VISIBLE SATELLITE
IMAGERY. SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND
THUNDERSTORMS IN THE ITCZ FROM 8N TO 10N BETWEEN 17W AND 19W.

ATLANTIC OCEAN TROPICAL WAVE ALONG 38W/39W SOUTH OF 13W MOVING
WEST 10 TO 15 KT. SHOWERS AND THUNDERSTORMS ARE IN THE ITCZ.
NO SHOWERS AND THUNDERSTORMS ARE NORTH OF 10N. STRATIFORM
CLOUDS ARE NORTH OF 11N BETWEEN 30W AND 40W.

ATLANTIC OCEAN TROPICAL WAVE IS ALONG 51W SOUTH OF 15N MOVING
WEST 10 TO 15 KT. CURRENT VISIBLE IMAGERY SHOWS CYCLONIC FLOW
ESPECIALLY NEAR 10N53W. SHOWERS AND THUNDERSTORMS ARE SEEN FROM
10N TO 11N BETWEEN 53W AND 55W. ISOLATED MODERATE SHOWERS AND
THUNDERSTORMS ARE WEST OF THIS WAVE...FROM 10N TO 17N BETWEEN
THE WAVE AND 60W.

WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 79W/80W SOUTH OF
15N MOVING WEST 10 TO 15 KT. WATER VAPOR IMAGERY SHOWS THAT
THIS WAVE IS IN AN AREA OF UPPER LEVEL NORTHEASTERLY WIND FLOW
AND MIDDLE TO UPPER LEVEL DRY AIR FROM 10N TO 17N BETWEEN 70W
AND 86W. SOME CLOUDS AND PRECIPITATION FROM THE ITCZ ARE
INVADING THE AREA OF DRY AIR...NOW SOUTH OF 11N BETWEEN THE
COLOMBIA COAST AND THE NICARAGUA/COSTA RICA COAST.

...THE ITCZ...

ITCZ 13N19W 8N30W 8N36W...8N40W 9N48W...9N52W 9N65W.
WIDELY SCATTERED TO SCATTERED MODERATE/ISOLATED STRONG
SHOWERS AND THUNDERSTORMS WITHIN 130 NM ON EITHER SIDE OF
12N21W 9N26W 6N37W 4N48W.

...DISCUSSION...

THE GULF OF MEXICO...
THE SPECIAL FEATURE...THE FORECAST OF THE FORMATION OF A SURFACE
LOW PRESSURE CENTER AND POSSIBLE DEVELOPMENT OF THAT SURFACE LOW
CENTER INTO A TROPICAL CYCLONE...IS THE MAIN POINT OF INTEREST.
AN UPPER LEVEL RIDGE...ABOUT WHICH DETAILS HAVE BEEN PROVIDED IN
THE SPECIAL FEATURE SECTION...RUNS FROM THE SOUTHWESTERN CORNER
BEYOND THE NORTHEASTERN CORNER OF THE AREA. MULTILAYERED CLOUDS
AND PRECIPITATION ARE WITHIN AT LEAST 210 NM ON EITHER SIDE OF
THE RIDGE.

THE CARIBBEAN SEA...
UPPER LEVEL FLOW FROM THE GULF OF MEXICO RIDGE IS PUSHING
NORTHEASTERLY WIND FLOW INTO THE CARIBBEAN SEA WEST OF 80W.
A MIDDLE TO UPPER LEVEL TROUGH RUNS FROM THE ATLANTIC OCEAN
NEAR 22N63W TO A CYCLONIC CIRCULATION CENTER NEAR 20N66W TO
EXTREME NORTHWESTERN VENEZUELA NEAR 10N70W JUST EAST OF LAKE
MARACAIBO. NORTHEASTERLY WIND FLOW AROUND THE TROUGH IS PUSHING
MIDDLE TO UPPER LEVEL NORTHEASTERLY WIND FLOW INTO THE CARIBBEAN
SEA BETWEEN 70W AND 80W. MIDDLE TO UPPER LEVEL DRY AIR FROM 10N
TO 17N BETWEEN 70W AND 86W.

THE ATLANTIC OCEAN...
A DEEP LAYER TROUGH RUNS FROM A CYCLONIC CIRCULATION CENTER
NEAR 31N57W TO 26N60W...TO A NORTHEASTERN CARIBBEAN SEA CYCLONIC
CIRCULATION CENTER NEAR 20N66W TO EXTREME NORTHWESTERN VENEZUELA
NEAR 10N70W JUST EAST OF LAKE MARACAIBO. A SURFACE TROUGH IS
ALONG 33N53W 24N60W INTO THE CARIBBEAN SEA NEAR 18N64W. ISOLATED
MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS ARE WITHIN
120 TO 180 NM EAST OF 31N56W 26N58W 24N64W 18N71W. UPPER LEVEL
ANTICYCLONIC WIND FLOW FROM THE GULF OF MEXICO RIDGE FLOWS INTO
THE ATLANTIC WATERS NORTH OF 20N WEST OF 70W. THIS FLOW IS
MEETING UP WITH MIDDLE TO UPPER LEVEL NORTHEASTERLY WIND FLOW TO
THE WEST OF THE DEEP LAYER ATLANTIC OCEAN-TO-VENEZUELA TROUGH.
MIDDLE TO UPPER LEVEL DRY AIR IS NORTH OF 20N BETWEEN THE DEEP
LAYER TROUGH AND THE ANTICYCLONIC FLOW AROUND THE GULF OF MEXICO
RIDGE. AN EASTERN ATLANTIC MIDDLE TO UPPER LEVEL TROUGH PASSES
BY THE MADEIRA ISLANDS AND REACHES THE CANARY ISLANDS. BROAD
UPPER LEVEL ANTICYCLONIC FLOW IS IN BETWEEN THE TWO ATLANTIC
TROUGHS. BROAD SURFACE ANTICYCLONIC FLOW COVERS THE ATLANTIC
WATERS TO THE EAST AND WEST OF THE 33N53W 18N64W SURFACE TROUGH.

$$
MT


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