[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251755
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON OCT 25 2010

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION RICHARD IS CENTERED NEAR 17.8N 90.2W AT
25/1500 UTC OR ABOUT 125 NM S OF CAMPECHE MEXICO MOVING W-NW AT
7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM
SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SATELLITE
IMAGERY SHOWS VERY LITTLE DEEP CONVECTION LEFT IN THE VICINITY
OF RICHARD AS IT CONTINUES TO WEAKEN OVER NORTHERN GUATEMALA AND
THE SOUTHERN YUCATAN PENINSULA. SCATTERED SHOWERS AND ISOLATED
TSTMS ARE WITHIN 150 NM IN THE NE QUADRANT AND 120 NM OF CENTER
ALL OTHER QUADRANTS. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 02N31W TO 10N24W MOVING W AT 10-15
KT. THE WAVE REMAINS AS A BROAD CYCLONIC PERTURBATION WITHIN THE
ITCZ REGION BETWEEN 21W AND 32W. AN EARLIER MORNING ASCAT PASS
AROUND 25/1110 UTC CONFIRMED NE WINDS TO 20 KT NORTHWEST OF THE
WAVE AXIS. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS
OCCURRING FROM  01N-11N BETWEEN 23W-32W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 13N17W 12N21W THEN RESUMES NEAR
04N32W 09N49W 09N61W. A SURFACE TROUGH IS ANALYZED FROM THE ITCZ
REGION NEAR 08N49W NE TO NEAR 16N44W. WHILE LOCATED BENEATH VERY
DRY AIR ALOFT DUE TO UPPER LEVEL W-NW WINDS...NO SIGNIFICANT
CONVECTION IS ASSOCIATED WITH THE SURFACE TROUGH. ELSEWHERE...
SCATTERED MODERATE CONVECTION IS FROM 04N-11N BETWEEN 17W-23W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL SHORTWAVE TROUGH LOCATES OVER THE SE CONUS WITH
AXIS EXTENDING ACROSS THE NW GULF FROM 30N87W TO 25N97W THEN SW
ACROSS CENTRAL MEXICO. WHILE THE WEAKENING SURFACE BOUNDARY
CONTINUES MOVING ACROSS NORTHERN GEORGIA AND THE CAROLINAS THIS
AFTERNOON...LOW-LEVEL SOUTHERLY CONVERGENCE ACROSS THE NE GULF
IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 29N W OF
87W..INCLUDING INLAND PORTIONS OF SOUTHERN ALABAMA AND THE
FLORIDA PANHANDLE. BETWEEN THE UPPER LEVEL TROUGH AXIS AND AN
UPPER LEVEL ANTICYCLONE CENTERED OVER THE NW CARIBBEAN NEAR
18N81W...DRY AND SUBSIDENT SOUTHWESTERLY FLOW ALOFT COVERS THE
REMAINDER OF THE GULF. THIS UPPER LEVEL ENVIRONMENT IN TURN IS
SUPPORTING A SURFACE RIDGE ACROSS MUCH OF THE GULF NORTH AND
NORTHWEST OF T.D. RICHARD AS IT WEAKENS OVER THE YUCATAN
PENINSULA. THE SURFACE RIDGE AXIS EXTENDS FROM THE W ATLC ACROSS
CENTRAL FLORIDA ALONG 28N83W TO 26N91W TO A WEAK 1015 MB HIGH
CENTERED OVER EAST-CENTRAL MEXICO NEAR 20N97W. MOSTLY FAIR
CONDITIONS ACCOMPANY THIS SURFACE RIDGE WITH MAINLY HIGH LEVEL
CIRRUS OUTFLOW FROM RICHARD STREAMING OVER THE SE GULF.

CARIBBEAN SEA...
A BROAD UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE NW
CARIBBEAN NEAR 18N81W AND EXTENDS ITS INFLUENCE BETWEEN 66W TO
BEYOND 95W AND INTO THE E PACIFIC REGION. T.D. RICHARD IS
LOCATED ON THE NORTHWESTERN PERIPHERY OF THE UPPER LEVEL
CIRCULATION PROVIDING MARGINAL OUTFLOW ALOFT...HOWEVER THE
SYSTEM CONTINUES TO WEAKEN DUE TO INCREASING DEEP LAYER SHEAR
LOCATED TO THE NW OVER THE GULF OF MEXICO AND FRICTION OVER
LAND. WITH AN UPPER LEVEL DIFFLUENT PATTERN IN PLACE OVER THE NW
CARIBBEAN AND CONVERGENT LOW-LEVEL E-SE TRADEWINDS...SCATTERED
SHOWERS AND ISOLATED TSTMS ARE OCCURRING FROM 14N-20N BETWEEN
80W-86W. ANOTHER AREA OF WEAKENING CONVECTION IS EMERGING OFF
THE NE PORTION OF THE YUCATAN PENINSULA MOVING INTO THE YUCATAN
CHANNEL. ELSEWHERE OVER THE REMAINDER OF THE CARIBBEAN...A
WESTERN ATLC SURFACE RIDGE EXTENDS TO SOUTHWARD TO 15N PROVIDING
THE BASIN WITH MODERATE TO FRESH TRADES THAT ARE FORECAST TO
PERSIST THROUGH TUESDAY.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE AXIS EXTENDS FROM THE NW CARIBBEAN SEA
ACROSS CENTRAL CUBA TO BEYOND 32N74W AND SUPPORTS A 1026 MB
SURFACE HIGH CENTERED NEAR 34N64W. WHILE MOST OF THE W ATLC IS
INFLUENCED BY THIS SURFACE HIGH...A SHEAR LINE ENTERS THE
DISCUSSION AREA NEAR 31N46W AND EXTENDS SW ALONG 26N55W TO
24N70W. AN EARLIER MORNING ASCAT PASS AROUND 25/1246 UTC
DEPICTED STRONGER NE WINDS WITHIN 120 NM NORTH OF THE SHEAR LINE
AXIS BETWEEN 49W-67W. LOW-LEVEL SPEED CONVERGENCE ALONG WITH A
WEAK UPPER LEVEL SHORTWAVE TROUGH ALONG 28N60W TO 24N66W IS
GENERATING AN AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS
WITHIN 90 NM EITHER SIDE OF THE SHEAR LINE BETWEEN 52W-63W.
ELSEWHERE ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER
SIDE OF THE SHEAR LINE. FARTHER EAST...A 1010 MB LOW IS CENTERED
NEAR 23N39W AND EXTENDS A SURFACE TROUGH SOUTH ALONG 21N39W TO
17N41W. THIS SURFACE LOW COLLOCATES WITH AN UPPER LEVEL LOW
CENTERED NEAR 21N39W AND CONTINUES TO GENERATE AN AREA OF
SCATTERED SHOWERS AND ISOLATED TSTMS FROM 24N-30N BETWEEN
30W-43W. AN UPPER LEVEL DIFFLUENT ZONE LOCATED N AND NE OF THE
UPPER LEVEL LOW IS CONTINUING TO SUSTAIN AND ENHANCE THE ONGOING
CONVECTION. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE
INFLUENCE OF A SURFACE RIDGE AXIS ALONG 23W DIPPING SOUTHWARD TO
THE CAPE VERDE ISLANDS AND ANCHORED BY A QUASI-STATIONARY 1031
MB HIGH CENTERED EAST OF THE AZORES NEAR 38N21W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
HUFFMAN




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