[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 012337
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON 01 NOV 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLC 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE OVER THE E CARIBBEAN IS REPOSITIONED FARTHER E
ALONG 67W S OF 20N MOVING W 10-15 KT. 1200 UTC VERTICAL
SOUNDINGS FROM ST. MAARTEN AND SAN JUAN PUERTO RICO BOTH
INDICATE A RELATIVELY WELL-DEFINED NE TO SE WIND SHIFT IN THE
LOWEST 200 MB OF THE ATMOSPHERE SO IT SEEMS LIKELY THAT THE WAVE
HAS JUST RECENTLY PASSED PUERTO RICO. ALTHOUGH SATELLITE IMAGERY
SHOWS BROAD CYCLONIC CURVATURE TO THE FLOW OVER THE E
CARIBBEAN...THE AXIS APPEARS TO BE CENTERED NEAR THE MONA
PASSAGE. THIS POSITION IS ALSO NEAR THE MOST WIDESPREAD
CONVECTIVE ACTIVITY NEAR THE LESSER ANTILLES. SCATTERED MODERATE
CONVECTION FROM 13N-17N BETWEEN 62W-67W. OTHER WIDELY SCATTERED
SHOWERS/TSTMS EXTEND FROM THE ABC ISLANDS TO PUERTO RICO AND THE
VIRGIN ISLANDS...BUT MUCH OF THIS ACTIVITY IS ALSO BEING
ENHANCED BY A WEAKENING FRONTAL BOUNDARY JUST N OF THE ISLANDS.

TROPICAL WAVE LOCATED OVER THE YUCATAN PENINSULA ALONG 88W/89W S
OF 23N MOVING W 10 KT. A GOOD CHUNK OF THE ENERGY ALONG THE
WAVE'S NORTHERN EXTENT IS BEING SHEARED NWD OVER THE GULF OF
MEXICO ALONG STRONG SE/S FLOW...WHILE THE MAIN AXIS CONTINUES TO
MOVE SLOWLY W. ISOLATED SHOWERS/TSTMS HAVE FORMED OVER THE
YUCATAN PENINSULA AS WELL AS WITHIN 30 NM OF A LINE FROM CANCUN
TO 25N88W OVER THE GULF.

...ITCZ...

ITCZ AXIS IS ALONG 12N10W 6N30W 10N50W 12N70W 10N86W. SCATTERED
MODERATE CONVECTION WITHIN 30/45 NM WIDE BANDS 110 NM N AND 220
NM S OF THE AXIS BETWEEN 18W-25W. SCATTERED TO WIDELY SCATTERED
MODERATE WITHIN 220 NM OF THE AXIS BETWEEN 25W-39W. SCATTERED
MODERATE WITHIN 90 NM OF THE AXIS BETWEEN 50W-55W. NUMEROUS
MODERATE/STRONG 100 NM INLAND OF THE VENEZUELA/COLOMBIA COAST
BETWEEN 68W-75W. SCATTERED MODERATE OVER THE SW CARIBBEAN...
NICARAGUA...AND HONDURAS FROM 10N-16N BETWEEN 78W-86W. WIDELY
SCATTERED MODERATE OVER PANAMA.

...DISCUSSION...

TEXAS COAST AND NORTHERN MEXICO...
A COUPLE OF FRONTAL BOUNDARIES ARE CURRENTLY AFFECTING PARTS OF
THE TEXAS COAST AND NORTHERN MEXICO AS A POTENT UPPER LEVEL TROF
SWINGS OUT OF THE SOUTHERN ROCKIES INTO THE WESTERN HIGH PLAINS.
A STATIONARY FRONT EXTENDS OFF THE GULF COAST NEAR THE
TEXAS/LOUISIANA BORDER THEN SWWD ABOUT 30 NM OFFSHORE BEFORE
MOVING INLAND AGAIN BETWEEN CORPUS CHRISTI AND BROWNSVILLE TO
NEAR MONTERREY AND MONCLOVA MEXICO. THERE IS VERY LITTLE WIND
SHIFT ACROSS THIS FRONT ALTHOUGH STRONG 15-20 KT SLY FLOW OVER
THE GULF WATERS LIES ADJACENT TO WEAKER 5-10 KT SE FLOW OVER E
TEXAS. TEMPERATURES FALL FROM THE LOWER 80S F SOUTH OF THE FRONT
TO THE UPPER 60S AND LOWER 70S F OVER E TEXAS. IN ADDITION...
SCATTERED TSTMS HAVE BEEN DEVELOPING ALONG THE FRONT AND ARE
MOVING INLAND OVER E TEXAS AND W LOUISIANA WITH TRAINING
PRODUCING HEAVY RAINFALL OVER THE SAME AREAS. FARTHER W...A
SECOND AND MUCH STRONGER COLD FRONT IS SWINGING THROUGH W TEXAS
AND NORTHERN MEXICO FROM NEAR ABILENE TO DEL RIO TEXAS THEN WWD
JUST N OF CHIHUAHUA MEXICO. TEMPERATURES ACROSS THIS FRONT DROP
FROM THE LOWER 70S F OVER E TEXAS TO THE UPPER 40S F OVER SE NEW
MEXICO AND N MEXICO. A BROAD UPPER LEVEL COLD CORE LOW IS
CENTERED TO THE W OF THE FRONT OVER SRN NEW MEXICO AND IS
PRODUCING SCATTERED SHOWERS AND EMBEDDED TSTMS PRIMARILY N OF
THE RIO GRANDE VALLEY.

REMAINDER OF GULF OF MEXICO AND WEST ATLANTIC...
STRONG DEEP-LAYERED RIDGING CONTINUES TO PRODUCE RELATIVELY FAIR
WEATHER OVER THE AREA. A 1022 MB SFC HIGH IS CENTERED ABOUT 430
NM E OF FLORIDA NEAR 30N73W WITH RIDGE EXTENDING FROM SOUTH
CAROLINA TO 27N50W. A STRONG MID/UPPER LEVEL HIGH IS CENTERED
NEAR 29N77W AND A LARGE AREA OF MODERATE/STRONG SUBSIDENCE IS
WITHIN 500-800 NM OF THIS FEATURE...KEEPING THE AREA MOSTLY DRY.

CARIBBEAN AND TROPICAL ATLANTIC W OF 50W...
THE MESSY WEATHER CONTINUES OVER THE E CARIBBEAN AS A TROPICAL
WAVE...A WEAKENING STATIONARY FRONT...AND FAVORABLE UPPER LEVEL
DYNAMICS PRODUCE SCATTERED SHOWER/TSTMS FROM 70W EWD INTO THE
ATLC. A MID/UPPER LOW IS LOCATED OVER THE S COAST OF HISPANIOLA
AND IS RETROGRADING SWWD WHILE CONTINUING TO DRAW A LARGE SWATH
OF MOISTURE FROM 10N-21N E OF 70W. SCATTERED MODERATE CONVECTION
IS FEEDING OFF THIS MOISTURE FROM 12N-18N BETWEEN 57W-67W WITH
HEAVY RAINFALL AFFECTING THE ISLANDS FROM GUADELOUPE SWD TO
GRENADA. THE STATIONARY FRONT EXTENDS ALONG 20N51W 19N67W AND IS
PRODUCING WIDELY SCATTERED SHOWERS/TSTMS 75 NM ON EITHER
SIDE...SOME OF WHICH ARE SPREADING OVER THE VIRGIN ISLANDS AND
PUERTO RICO. OVER THE W CARIBBEAN...DRY AIR IS MOVING ACROSS THE
BAHAMAS AND CUBA AND PRODUCING FAIR WEATHER S OF 17N. AN UPPER
LEVEL RIDGE IS ALIGNED JUST OFF THE PANAMA/COSTA RICA COAST WITH
UPPER LEVEL DIVERGENCE PRODUCING WIDELY SCATTERED MODERATE
CONVECTION FROM 10N-16N BETWEEN 78W-85W.

ATLANTIC EAST OF 50W...
A COLD FRONT EXTENDS INTO THE AREA ALONG 32N34W 26N40W 20N51W
WITH A FLAT AND BROAD UPPER LEVEL TROF REACHING AS FAR S AS 25N.
MOST OF THE CONVECTION AHEAD OF THE FRONT HAS DISSIPATED WITH
ONLY ISOLATED SHOWERS NOW FROM 25N-32N BETWEEN 26W-34W. WESTERLY
FLOW EXTENDS S OF THE TROF TO 10N...WHERE AN UPPER RIDGE IS
ALIGNED ALONG THE ITCZ AND ENHANCING AREAS OF MODERATE
CONVECTION. FARTHER E...STRONG UPPER LEVEL RIDGING LIES ALONG
15W AND MOVING E OVER W AFRICA AS A STRONG SHORTWAVE DROPS SE
FROM THE AZORES. A 1020 MB SFC HIGH IS LOCATED IN THE VICINITY
OF THE CANARY AND MADEIRA ISLANDS WHICH IS STRENGTHENING THE
NELY FLOW MOVING ALONG THE MOROCCAN COAST INTO THE ATLC.

$$
BERG




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