[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301813
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT 30 APR 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 1745 UTC.

...THE ITCZ...

ITCZ 10N6W 3N20W 3N30W 4N40W 5N50W 7N61W. ISOLATED MODERATE TO
LOCALLY STRONG SHOWERS AND THUNDERSTORMS FROM 2N TO 6N BETWEEN
13W AND 20W...FROM THE EQUATOR TO 7N BETWEEN 30W AND 50W...AND
FROM 7N TO 9N BETWEEN 53W AND 58W.

...DISCUSSION...
THE GULF OF MEXICO...
MODERATE TO STRONG SURFACE RETURN FLOW HAS DEVELOPED ACROSS THE
ENTIRE GULF OF MEXICO...IN ADVANCE OF AN APPROACHING COLD FRONT.
THIS FRONT ALREADY HAS ENTERED THE NORTHWESTERN GULF WATERS...
WITH WINDS BEHIND IT STRONG ENOUGH FOR A GALE WARNING. STRONG
SHOWERS AND THUNDERSTORMS ARE OCCURRING WITHIN 30 TO 40 NM ON
EITHER SIDE OF 29N91W 30N88W 31N86W FROM SOUTHEASTERN LOUISIANA
TO SOUTHWESTERN ALABAMA AND THE NORTHWESTERN CORNER OF THE
FLORIDA PANHANDLE. THIS PRECIPITATION IS FALLING IN THE AREA
OF TWO SQUALL LINES JUST EAST OF THE FRONT. GALE FORCE WINDS
ARE FORECAST WEST OF THE FRONT UNTIL JUST AFTER SUNSET. A
WELL-DEFINED CLOUD LINE MARKS THE FRONT ON VISIBLE SATELLITE
IMAGERY. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG
THE FRONT LATER TODAY AS ENOUGH AVAILABLE LOW LEVEL MOISTURE AND
IMPROVING UPPER LEVEL DYNAMICS HELP TO PRODUCE A DEVELOPING LINE
OF STRONG SHOWERS AND THUNDERSTORMS...MAINLY NORTH OF 27N...AS
THE FRONT PUSHES INTO THE NORTH CENTRAL GULF. THE UPPER TROUGH
BEGINS TO LIFT NORTHEASTWARD SUNDAY WITH DECREASING UPPER LEVEL
SUPPORT AND SHOWERS AND THUNDERSTORMS ALONG THE FRONT AS IT
BEGINS TO BECOME STATIONARY AND WEAKEN IN THE VICINITY OF LAKE
OKEECHOBEE BY LATE SUNDAY. VISIBLE SATELLITE IMAGERY REVEALS
A LARGE AREA OF SMOKE MOVING NORTHWARD FROM SOUTHERN MEXICO
AND CENTRAL AMERICA INTO THE WESTERN GULF.

THE CARIBBEAN SEA...
WELL DEFINED MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM NORTHERN
SECTIONS OF SOUTH AMERICA NORTHWESTWARD TO CENTRAL AMERICA...
AND INTO SOUTHERN MEXICO. A MIDDLE TO UPPER LEVEL TROUGH IS
DIGGING INTO THE CARIBBEAN SEA EAST OF 70W FROM THE CENTRAL
AND WESTERN ATLANTIC OCEAN...RUNNING FROM A CYCLONIC CIRCULATION
CENTER NEAR 33N57W TO 26N56W TO 20N62W TO 12N66W. MIDDLE TO
UPPER LEVEL DRY AIR ABOUNDS EAST OF 79W. BROKEN TO OVERCAST HIGH
CLOUDS HAVE MOVED INTO THE SOUTHWESTERN CORNER OF THE AREA...
SOUTH OF 14N WEST OF 78W...THANKS TO THE RIDGE. ISOLATED
SHOWERS...WEAKENING...IN EASTERN PANAMA. POSSIBLE SHOWERS IN
LINES OF LOW CLOUDS IN MANY SECTIONS...BUT WITH THE GREATEST
POSSIBILITY NORTH OF 14N EAST OF 68W...AND FROM 12N TO 14N
BETWEEN 70W AND 80W. MOISTURE AND THE PROBABILITY FOR SHOWERS
AND THUNDERSTORMS WILL REMAIN HIGHEST OVER THE EASTERN CARIBBEAN
SEA DURING THE WEEKEND WITH GENERALLY DRY CONDITIONS ELSEWHERE
OVER THE CENTRAL AND WESTERN CARIBBEAN.

THE ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL RIDGE ALONG THE U.S.A. EAST COAST...
SENDING MIDDLE TO UPPER LEVEL NORTHWESTERLY WIND FLOW TOWARD
THE BASE OF AN ATLANTIC OCEAN-TO-SOUTHEASTERN CARIBBEAN SEA
TROUGH. THE TROUGH RUNS FROM A CYCLONIC CIRCULATION CENTER
NEAR 33N57W TO 26N56W TO 20N62W TO 12N66W. ONE SURFACE FEATURE
RELATED TO THIS MIDDLE TO UPPER LEVEL TROUGH IS A 1016 MB LOW
PRESSURE CENTER NEAR 33N58W. A DISSIPATING COLD FRONT EXTENDS
FROM THE LOW TO 30N57W 26N60W 19N66W. GALE FORCE WINDS EXIST
TO THE NORTH OF THIS LOW CENTER. A TROUGH RUNS FROM A SECOND
1016 MB LOW CENTER NEAR 26N55W TO 20N56W 16N60W 15N64W.
A SECOND TROUGH IS ALONG 24N49W 18N55W. WIDELY SCATTERED TO
SCATTERED MODERATE/ISOLATED STRONG SHOWERS AND THUNDERSTORMS
ARE FOUND FROM 31N TO 34N BETWEEN 52W AND 59W...FROM 20N TO 31N
BETWEEN 40W AND 53W...BECOMING MUCH MORE ISOLATED FROM 17N TO
20N BETWEEN 46W AND 58W. MIDDLE TO UPPER LEVEL WESTERLY TO
SOUTHWESTERLY WIND FLOW CONTINUES ACROSS THE ATLANTIC WATERS
UNTIL REACHING AN AREA SOMEWHERE NEAR THE CANARY ISLANDS...WHERE
THE FLOW BECOMES DIFFLUENT. DEEP LAYER CYCLONIC FLOW IS NORTH OF
30N...AROUND A TROUGH AND CYCLONIC CIRCULATION CENTER NEAR
41N27W ON WATER VAPOR IMAGERY AND NEAR 42N30W AT THE SURFACE.
SOUTHERN END OF AN EASTERN ATLANTIC COLD FRONT REACHES 32N18W...
JUST WEST OF THE MADEIRA ISLANDS. DISSIPATING COLD FRONT 32N18W
TO 28N22W. DISSIPATING STATIONARY FRONT 28N22W 27N26W 24N30W
22N40W. UPPER LEVEL ANTICYCLONIC WIND FLOW IS INDICATED FROM 10N
TO 20N BETWEEN 30W AND 40W. DRY AIR AND DUST FROM AFRICA COVER
THE ATLANTIC WATERS FROM THE ITCZ TO 23N BETWEEN AFRICA AND 40W.

$$
MT

This weather bulletin was brought to you by:
www.nashvilleweather.net