[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 261119
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN NOV 26 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1100 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N13W 7N29W 8N47W 7N58W. SCATTERED
MODERATE CONVECTION IS WITHIN 180 NM S OF THE AXIS BETWEEN
27W-36W. ISOLATED MODERATE IS FROM 4N-14N BETWEEN 26W-52W
ENHANCED BY THE UPPER LOW E OF THE WINDWARD ISLANDS.

...DISCUSSION...
THE GULF OF MEXICO...
THE WEATHER ACROSS THE GULF IS FAIRLY UNEVENTFUL AS SFC HIGH
PRES CONTINUES TO DOMINATE THE AREA. BREEZY 15-20 KT NE TO E
WINDS IN THE ERN AND CNTRL GULF IS ADVECTING SOME LOW-LEVEL
CLOUDS AND ISOLATED SHOWERS ACROSS CENTRAL AND SOUTH
FLORIDA...MAINLY THE ERN HALF OF THE STATE...WITH SOME BROKEN
CLOUDS PUSHING W ACROSS THE GULF WATERS.  HOWEVER BECAUSE OF THE
WIDESPREAD STRONG SUBSIDENCE ABOVE THE LOW-LAYER OF MOISTURE
THERE IS LIMITED DEPTH TO THE CLOUDS. LIGHTER E TO SE WINDS
EXIST IN THE WRN GULF. IN THE UPPER LEVELS...A RIDGE EXTENDS
FROM THE EPAC ACROSS CENTRAL MEXICO INTO THE WESTERN HALF OF THE
GULF. SLIGHT UPPER TROUGHING LIES ACROSS THE EASTERN HALF. GFS
SHOWS THE TROUGH LIFTING OUT WITH THE RIDGE BUILDING ACROSS THE
AREA. THIS SHOULD ALLOW TEMPS TO REMAIN NEAR OR SLIGHTLY ABOVE
NORMAL OVER THE NEXT FEW DAYS. THE NEXT AIRMASS CHANGE IS
ANTICIPATED TO AFFECT THE AREA LATE IN THE WEEK AS A POTENTIAL
STRONG COLD FRONT APPROACHES.

THE CARIBBEAN SEA...
THE SFC LOW PRES SYSTEM IN THE SW CARIB HAS WEAKENED TO OPEN
TROUGH...WHICH IS ANALYZED ALONG 78W FROM 9N-17N. DESPITE THE
STRUCTURAL DECAY...SHOWER ACTIVITY HAS INCREASED SLIGHTLY THIS
MORNING WITH SCATTERED MODERATE CONVECTION NOTED ON IR IMAGERY
WITHIN 120 NM OF THE TROUGH AXIS S OF 15N. A SLOWLY WEAKENING
STATIONARY FRONT EXTENDS FROM THE WINDWARD PASSAGE JUST W OF
JAMAICA TO THE COAST OF HONDURAS. DEEP MOISTURE IS VERY LIMITED
ALONG THE FRONT WITH ONLY ISOLATED SHOWERS WITHIN 150 NM OF THE
SFC BOUNDARY. A VERY BROAD UPPER LEVEL RIDGE...CENTERED NEAR
THE ABC ISLANDS...IS ADVECTING MOISTURE FROM THE ITCZ AND
SPREADING IT ABOVE THE SFC FRONT INTO THE ATLC WITH CONSIDERABLE
MID-HIGH LEVEL CLOUDINESS AND EMBEDDED SHOWERS NOTED BETWEEN
72W-82W. VERY DRY AIR/STRONG SUBSIDENCE LIES ABOVE THE ERN AND
THE EXTREME WRN CARIB SUPPRESSING ANY DEEP CLOUDINESS. SCATTERED
SHOWERS HAVE FORMED OVER THE PAST COUPLE OF HOURS JUST E OF THE
LESSER ANTILLES...SOME OF THIS MAY MOVE ACROSS THE ISLANDS LATER
THIS MORNING DRIVEN BY MODERATE TRADE WINDS. LITTLE CHANGE IS
EXPECTED OVER THE NEXT FEW DAYS. LATE THIS WEEK...TRADES WILL
LIKELY INCREASE AS STRONG HIGH PRES DEVELOPS TO THE N.

THE ATLANTIC OCEAN...
VERY DRY AIR ALOFT AND PATCHES OF LOW-LEVEL MOISTURE COVERS THE
AREA W OF A WEAKENING STATIONARY FRONT THAT EXTENDS FROM E OF
BERMUDA TO THE WINDWARD PASSAGE ALONG 32N59W 25N67W 20N74W. A
WEAK AREA OF LOW PRES...ANALYZED AT 1014 MB...HAS DEVELOPED
ALONG THE BOUNDARY NEAR 30N62W. MULTILAYERED CLOUDS WITH
EMBEDDED SHOWERS ARE ASSOCIATED WITH THE WEAK LOW/FRONTAL
BOUNDARY AND EXTEND WITHIN 240 NM E OF THE FRONT N OF 25N AND
WITHIN 150 NM EITHER SIDE S OF 25N. A NARROW UPPER TROUGH
STRETCHES FROM 32N43W 22N52W TO AN UPPER LOW IN THE DEEP TROPICS
NEAR 10N56W. UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER LOW AND
AN AMPLIFIED RIDGE TO ITS E NEAR 9N39W IS ENHANCING SCATTERED
SHOWERS AND TSTMS NEAR AND N OF THE ITCZ FROM 4N-14N BETWEEN
33W-52W. THIS AMPLIFIED MID/UPPER LEVEL RIDGE BECOMES HIGHLY
ELONGATED AS THE NRN BRANCH OF THE SHORTWAVE TO ITS W IS
IMPINGING ON IT. THE AXIS EXTENDS FROM THE HIGH CENTER IN THE
TROPICS NORTHEASTWARD ALONG 23N33W 32N26W. AN AREA OF MID/UPPER
LEVEL MOISTURE WITH EMBEDDED SCATTERED SHOWERS IS ALSO BEING
PRODUCED BY UPPER DIFFLUENCE N OF 25N BETWEEN 31W-40W. AN UPPER
LEVEL TROUGH CLIPS THE EXTREME ERN PORTION OF THE AREA EXTENDING
FROM SPAIN ACROSS WRN AFRICA TO THE CAPE VERDE ISLANDS. PLENTY
OF DRY STABLE AIR ALOFT IS LOCATED W OF THE TROUGH AXIS OUT TO
30W. AT THE SFC...MODERATE HIGH PRES RIDGING IS A GOOD PHRASE TO
DESCRIBE THE PATTERN ACROSS THE SUBTROPICAL ATLC SUPPORTED BY A
1023 MB HIGH NEAR 30N27W AND A 1022 MB HIGH NEAR THE MADEIRA
ISLANDS. THIS HIGH PRES IS INTERRUPTED BY THE FRONTAL
BOUNDARY/WEAK LOW MENTIONED E OF BERMUDA.

$$
CANGIALOSI




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