AXNT20 KNHC 070544
TWDAT
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.
BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.
...SPECIAL FEATURES...
TROPICAL DEPRESSION IDA IS CENTERED NEAR 16.2N 84.0W AT 07/0300
UTC OR ABOUT 95 NM ENE OF LIMON HONDURAS MOVING N AT 6 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED
WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/ WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS. IDA HAS RE-EMERGED INTO THE CARIBBEAN WATERS
OFF THE COAST OF HONDURAS. SCATTERED MODERATE/STRONG CONVECTION
COVERS THE AREA FROM 16N-17N BETWEEN 83W-85W AND FROM 17N-20N
BETWEEN 80W-85W.
...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 34W S OF 14N MOVING W NEAR 15 KT. WAVE
REMAINS WITHIN A BROAD AREA OF DEEP LAYERED MOISTURE ON THE
TOTAL PRECIPITABLE WATER IMAGERY. WAVE IS JUST TO THE SE OF AN
UPPER TROUGH AND BENEATH AN UPPER RIDGE WHICH DRAWING MOISTURE
AWAY FROM THE WAVE ITSELF. ANY CONVECTION IS ASSOCIATED WITH THE
ITCZ.
TROPICAL WAVE IS ALONG 56W/57W S OF 16N MOVING W NEAR 15 KT.
WEAK LOW LEVEL CURVATURE IS OBSERVED ON SATELLITE IMAGERY AND IT
IS IN AN AREA OF SLIGHT UPPER LEVEL MOISTURE THUS NO SIGNIFICANT
DEEP CONVECTION. SCATTERED SHOWERS ARE FROM 15N-18N BETWEEN
52W-56W.
...ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 8N11W 6N22W 7N34W 6N43W 8N55W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 4N-7N BETWEEN 10W-14W AND FROM 2N-10N BETWEEN 22W-33W.
...DISCUSSION...
GULF OF MEXICO...
A 1027 MB HIGH IS CENTERED OVER EASTERN NORTH CAROLINA WITH A
SURFACE RIDGE EXTENDING SW AND SE COVERING THE W ATLC AND GULF
OF MEXICO GIVING MOST OF THE GULF NE TO E FLOW. THIS FLOW
FILTERS INTO THE SW GULF AND BAY OF CAMPECHE NEAR A SURFACE
TROUGH THAT EXTENDS FROM 18N93W THROUGH A 1010 MB LOW NEAR
19N95W TO 23N96W. THE REMAINDER OF THE GULF IS DOMINATED BY AN
UPPER RIDGE ANCHORED IN THE CENTRAL CARIBBEAN. THE SURFACE
LOW/TROUGH IS SUPPORTED ALOFT BY AN UPPER LEVEL SHORTWAVE TROUGH
WITH AN AXIS EXTENDING FROM NE MEXICO NEAR TAMPICO TO 19N95W.
THE SURFACE FEATURES ALONG WITH DIFFLUENCE E OF THE UPPER LEVEL
TROUGH AXIS IS GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS S OF 27N BETWEEN 88W-97W. SCATTERED
SHOWERS/ ISOLATED THUNDERSTORMS ARE MOVING WESTWARD WITHIN 60 NM
ALONG THE N COAST OF CUBA E OF 88W.
CARIBBEAN SEA...
THE MOST SIGNIFICANT FEATURE FOR THE CARIBBEAN TONIGHT IS
TROPICAL DEPRESSION IDA. THE UPPER LEVELS OF THE CARIBBEAN ARE
DOMINATED BY A LARGE UPPER RIDGE ANCHORED IN THE CENTRAL
CARIBBEAN NEAR 14N74W AND COVERS THE GULF OF MEXICO AND THE W
ATLC AS WELL. A WEAK SURFACE TROUGH IS ANALYZED ALONG 77W/78W S
OF 13N TO INLAND OVER E PANAMA AND IS GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS S OF 13N FROM 73W-79W. THE E
CARIBBEAN IS UNDER MODERATE SUBSIDENCE AND DRIER AIR.
HOWEVER...ISOLATED LOW LEVEL FAST MOVING SHOWERS DOTS THE
REMAINDER OF THE CARIBBEAN USHERED IN ON MODERATE/STRONG
EASTERLY TRADEWINDS.
ATLANTIC OCEAN...
A SURFACE RIDGE CONTROLS THE W ATLC W OF 65W ANCHORED ON A 1027
MB HIGH CENTERED OVER EASTERN NORTH CAROLINA. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE WITHIN 60 NM OF LINE FROM 26N65W INTO
THE GULF OF MEXICO THROUGH THE STRAITS OF FLORIDA NEAR 24N80W.
FARTHER EAST...A COLD FRONT ENTERS THE DISCUSSION AREA NEAR
32N56W EXTENDING SW TO 26N63W WITH A SURFACE TROUGH EXTENDING
FROM 30N58W TO 22N60W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ARE WITHIN 120 NM OF LINE FROM 25N62W TO BEYOND 32N54W. THE
FRONTAL SYSTEM IS SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH N OF
26N W OF 52W. THE E ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED ON A 1034 MB HIGH CENTERED OVER THE AZORES. AN
UPPER LEVEL TROUGH IS OVER THE E ATLC EXTENDING AN AXIS FROM
32N30W INTO THE TROPICS TO 16N51W. UPPER LEVEL DIFFLUENCE EAST
OF THE TROUGH AXIS IS GENERATING POSSIBLE ISOLATED SHOWERS N OF
THE AREA ASSOCIATED WITH THE TROPICAL WAVE ALONG 34W COVERING
THE AREA FROM 16N-26N BETWEEN 36W-44W.


forecast by WALLACE
updated at 105 AM EST SAT NOV 07 2009

AXPZ20 KNHC 071000
TWDEP
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT NOV 07 2009
TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM
THE EQUATOR TO 32N...EAST OF 140W.
BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0815 UTC.
...TROPICAL LOWS...
LOW PRES CENTERED NEAR 12N91W ESTIMATED AT 1006 MB AND IS NOW
MOVING N SLOWLY IN RESPONSE TO THE UPPER TROUGH IMMEDIATELY TO
ITS W WHICH IS ALSO CONTRIBUTING BOTH SOUTHWESTERLY WIND SHEAR
AND DRY AIR WHICH IS BEING ENTRAINED BY THE LOW. THE SYSTEM IS
EXPECTED TO DISSIPATE TO A TROUGH OVER THE NEXT 24 HOURS WITHIN
THIS HOSTILE ENVIRONMENT. CURRENTLY...SCATTERED MODERATE WITH
ISOLATED STRONG CONVECTION IS DISPLACED FROM THE LOW LEVEL
CENTER...BETWEEN 60 NM AND 180 NM IN THE NE QUADRANT OF THE LOW.
TWO SHIP REPORTS IN THE EASTERN SEMICIRCLE OF THE LOW REPORTED
WINDS IN THE 25 TO 30 KT RANGE AT 0600 UTC...BUT THESE WINDS
SHOULD RAPIDLY DIMINISH TODAY AS THE LOW WEAKENS.
LOW PRES CENTERED NEAR 12N116W IS ESTIMATED AT 1010 MB. THE
SURFACE LOW IS UNDER AN UPPER ANTICYCLONE...AND THE ASSOCIATED
UPPER DIFFLUENCE HAS BEEN ENHANCING CONVECTION. SCATTERED
MODERATE WITH ISOLATED STRONG CONVECTION LIES WITHIN 180 NM NW
AND SE QUADRANTS OF THE LOW. THIS LOW IS EXPECTED TO WEAKEN OVER
THE NEXT 24-36 HOURS AS THE UPPER JET TO ITS N SINKS
SOUTHWARD...PROVIDING 30 TO 40 KT OF SHEAR OVER THE SYSTEM.
...ITCZ...
THE ITCZ AXIS EXTENDS ALONG 07N77W TO 11N87W TO 07N97W TO
12N115W TO 08N140W. SCATTERED MODERATE CONVECTION CAN BE FOUND
NEAR PANAMA WITHIN 60 NM N AND 120 NM S OF THE ITCZ AXIS BETWEEN
78W AND 82W. SCATTERED MODERATE TO STRONG CONVECTION LIES WITHIN
90 NM S OF THE ITCZ AXIS BETWEEN 98W AND 101W.
...DISCUSSION...
N OF 20N...
AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 08N113W WITH A RIDGE
AXIS EXTENDING NE TO MANZANILLO...MEXICO AND CONTINUING N INTO
TEXAS. AN UPPER LOW LIES OVER THE NORTHERN GULF OF CALIFORNIA
NEAR 29N113W AND IS APPROACHING THIS RIDGE AXIS FROM THE W. THE
TROPICAL MOISTURE PLUME THAT EXTENDED FROM THE ITCZ REGION TO
THE EASTERN EDGE OF THIS UPPER LOW THIS TIME YESTERDAY HAS BEEN
CUT OFF. ONLY HIGH CLOUDS REMAIN...PRIMARILY OVER THE NORTHERN
HALF OF THE GULF OF CALIFORNIA AS WELL AS OVER NW MAINLAND
MEXICO. THIS UPPER LOW WILL CONTINUE E AWAY FROM THE FORECAST
AREA OVER THE NEXT FEW DAYS. THERE IS LITTLE INDICATION OF THE
UPPER LOW AT THE SURFACE WHERE A HIGH PRES RIDGE STEMMING FROM A
1032 MB HIGH NEAR 36N152W DOMINATES THE REMAINDER OF NORTH
WATERS. THE PRES GRADIENT BETWEEN THIS HIGH AND LOW PRES OVER
THE GULF OF CALIFORNIA HAS BROUGHT 20 KT NORTHERLY WINDS OFF THE
W COAST OF BAJA CALIFORNIA. THESE WINDS SHOULD DISSIPATE OVER
THE NEXT FEW HOURS AS A COLD FRONT BEARS DOWN ON THE HIGH PRES
SYSTEM FROM THE NW AND WEAKENS THE RIDGING. WHILE THIS FRONT IS
EXPECTED TO DISSIPATE BEFORE IT CAN REACH FORECAST WATERS...LONG
PERIOD NW SWELL FROM THE SYSTEM IS ALREADY BEGINNING TO PUSH
INTO NW WATERS WITH SIGNIFICANT WAVE HEIGHTS INCREASING TO 18 FT
OVER NW WATER THIS MORNING. HIGHEST SEAS WILL SHIFT E QUICKLY
TODAY ACROSS N WATERS...WITH THE LEADING EDGE OF THE SWELL TRAIN
PROGRESSING SE.
S OF 20N...
ASIDE FROM THE LOW PRES SYSTEMS DESCRIBED ABOVE AND THE GAP
WINDS DESCRIBED BELOW...EASTERLY TRADE WINDS ARE THE DOMINANT
FEATURE OF NOTE. 20 TO 25 KT TRADES ARE CURRENTLY LIMITED TO
BETWEEN 10N AND 20N W OF 127W...WITH A SMALL AREA OF 20 TO 25 KT
WINDS ASSOCIATED WITH THE LOW PRES SYSTEM NEAR 12N116W. THE AREA
OF STRONGEST TRADE WINDS WILL SHIFT S IN RESPONSE TO THE
AFOREMENTIONED REORGANIZATION OF THE HIGH PRES SYSTEM TO THE
NORTH. ANOTHER WEAK LOW PRES SYSTEM LIES NEAR 10N108W. ACCORDING
TO THE 0504 ASCAT PASS...THE LOW HAS A SMALL AREA OF 20 TO 25 KT
WINDS WITHIN 90 NM IN ITS N QUADRANT. SCATTERED MODERATE
CONVECTION CAN CURRENTLY BE FOUND WITHIN 90 NM NW AND 60
NM SE SEMICIRCLES OF THE LOW WHICH NOW LIES UNDER THE
ANTICYCLONE IN A FAVORABLE AREA FOR CONVECTION. CONDITIONS
SHOULD BECOME MORE HOSTILE FOR THE SYSTEM OVER THE NEXT DAY OR
TWO...AND THIS LOW IS EXPECTED TO DISSIPATE WITH LITTLE FANFARE.
GAP WINDS...
A PARTIAL ASCAT PASS FROM 0324 UTC SHOWED WINDS IN THE 30 TO 33
KT RANGE IN THE GULF OF TEHUANTEPEC. CONSIDERING THE PASS
OMITTED A PORTION OF THE AREA BELIEVED TO HAVE THE STRONGEST
WINDS AND THE FACT THAT ASCAT GENERALLY RUNS LOW WITH WINDS NEAR
GALE FORCE AND HIGHER...THERE IS LIKELY STILL A GALE HERE THAT
WILL CONTINUE THROUGH THE MORNING HOURS. HOWEVER...THERE IS A
CONSIDERABLE AMOUNT OF UNCERTAINTY WITH THE FORECAST FOR THE
STRENGTH AND POSITION OF LOW PRES IN THE BAY OF CAMPECHE...THE
PERSISTENT LOW PRES NEAR 12N91W THAT IS NOW DRIFTING N...AND
TROPICAL STORM IDA NOW OVER THE EASTERN GULF OF HONDURAS AND
FORECAST TO MOVE NORTHWARD AND STRENGTHEN. ALL OF THESE FACTORS
WILL INFLUENCE THE WIND...OR LACK OF WIND...IN THE GULF OF
TEHUANTEPEC OVER THE NEXT FEW DAYS. DEPENDING ON THE ORIENTATION
OF THE LOW PRES CENTERS N OF THE AREA...ANOTHER N SURGE MAY
OCCUR AS EARLY AS SUN IN THE GULF OF TEHUANTEPEC.


forecast by SCHAUER