[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162149 AAA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL.
205 PM EDT SAT JUL 16 2005

..AMENDED FOR 2100 UTC ADVISORY INFORMATION...

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
1715 UTC.

...SPECIAL FEATURE...

HURRICANE EMILY IS CENTERED NEAR 16.8N 78.8W OR ABOUT 130 MILES
...210 KM...SOUTH-SOUTHWEST OF MONTEGO BAY JAMAICA AND ABOUT 235
MILES... 375 KM...SOUTHEAST OF GRAND CAYMAN AT 16/2100 UTC
MOVING WNW 16 KT. MINIMUM CENTRAL PRESSURE IS 937 MB AND THE
MAXIMUM SUSTAINED WIND SPEED IS 135 KT WITH GUSTS TO 165 KT.
PLEASE REFER TO THE LATEST FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT5/ WTNT25 KNHC AND THE PUBLIC ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS.  EMILY
CONTINUES TO DISPLAY AN IMPRESSIVE SATELLITE APPEARANCE WITH ALL
THE SIGNS OF A DANGEROUSLY STRONG HURRICANE INCLUDING A
WELL-DEFINED AND CLEAR EYE...STRONG SURROUNDING CONVECTION WITH
VERY COLD CLOUD TOPS...AND GOOD UPPER LEVEL OUTFLOW WITH A
POLEWARD OUTFLOW JET. LATEST SATELLITE IMAGERY SHOWS NUMEROUS
CONVECTION WITH EMILY IS WITHIN 100-150 NM OVER THE SW
SEMICIRCLE AND WITHIN 200-250 NM OVER THE NE SEMICIRCLE
INCLUDING JAMAICA.  THIS ACTIVITY WILL CONTINUE TO PRODUCE VERY
HEAVY RAINFALL...STRONG WINDS...AND POSSIBLE FLOODING OVER
JAMAICA AND THE CAYMAN ISLANDS THIS AFTERNOON AND TONIGHT EVEN
THOUGH EMILY IS FORECAST TO BYPASS THESE LOCATIONS TO THE
SOUTH.

...TROPICAL WAVES...

TROPICAL WAVE OVER THE E ATLC ALONG 37W/38W S OF 17N MOVING W 25
KT. THE WAVE IS EMBEDDED WITHIN A LARGE SURGE OF LOW LEVEL
EASTERLIES AND AFRICAN DUST/DRY AIR.  AS A RESULT...THE WAVE IS
MOVING FASTER THAN USUAL AND CONVECTION IS SUPPRESSED N OF THE
ITCZ.  THE SATELLITE SIGNATURE HAS ALSO BECOME A BIT LESS
DEFINED BUT A PERSISTENT AREA OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS STILL OBSERVED WITHIN THE ITCZ MOVING W
WITH THE WAVE.

HIGH-AMPLITUDE TROPICAL WAVE OVER THE CENTRAL ATLC ALONG 52W S
OF 25N MOVING W 15 TO 20 KT.  THE WAVE IS NOW INTERACTING WITH
THE LEADING EDGE OF A STRONG LOW LEVEL EASTERLY SURGE AND
ASSOCIATED AFRICAN DUST/DRY AIR.  ADDITIONALLY...AN UPPER LEVEL
TROUGH TO THE WEST IS IMPARTING STRONG WLY FLOW ACROSS THE
WAVE.  AS A RESULT...STRONG SHEAR EXISTS WHICH IS CURRENTLY
LIMITING DEVELOPMENT EVEN THOUGH AN IMPRESSIVE AREA OF SCATTERED
STRONG CONVECTION ACCOMPANIES THE WAVE FROM 20N-27N BETWEEN
47W-53W. STRONG SW SHEAR IS EXPECTED TO CONTINUE OVER THIS
SYSTEM DURING THE NEXT FEW DAYS PULLING MUCH OF ENERGY AND
ASSOCIATED DEEP CONVECTION POLEWARD OF 20N.  HOWEVER...LOW LEVEL
MOISTURE FROM THIS WAVE IS EXPECTED TO ENTER THE WINDWARD
ISLANDS SUN POSSIBLY PRODUCING INCREASING SHOWERS/TSTMS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 15N15W 10N40W 13N50W 8N60W THEN
ACROSS N PORTIONS OF S AMERICA.  SCATTERED MODERATE CONVECTION
WITHIN 100 NM EITHER SIDE OF ITCZ BETWEEN THE COAST OF AFRICA
AND 30W AND FROM 37W-43W.  ISOLATED MODERATE TO STRONG
CONVECTION WITHIN 100 NM EITHER SIDE OF AXIS W OF 50W.

...DISCUSSION...

GULF OF MEXICO...
THE PATTERN ALOFT OVER THE GLFMEX IS COMPRISED OF A STRONG
MID-UPPER LEVEL RIDGE EXTENDING EXTENDING FROM THE SE UNITED
STATES SW ACROSS CENTRAL MEXICO...A MIDDLE TO UPPER LEVEL TROUGH
EXTENDING SWD FROM THE CENTRAL UNITED STATES OVER TEXAS INTO N
CENTRAL MEXICO...AND A RETROGRADING UPPER LOW OVER THE YUCATAN
PENINSULA.  TWO AREAS OF ACTIVE CONVECTION ARE NOTED TODAY...ONE
ALONG THE SE COAST OF TEXAS AND THE SECOND OVER THE W BAY OF
CAMPECHE AND COAST OF MEXICO FROM TAMPICO SWD TO THE ISTHMUS OF
TEHUANTEPEC. BOTH AREAS ARE EXPECTED TO SLOWLY SHIFT WESTWARD
OVER THE NEXT DAY OR SO AS THE CENTRAL U.S. TROUGH FRACTURES AND
BEGINS TO RETROGRADE.  ELSEWHERE...AREA SOUNDINGS SHOW THAT
DEEP-LAYERED MOISTURE REMAINS HIGH SUPPORTING ISOLATED TO WIDELY
SCATTERED SHOWERS AND TSTMS OVER THE OPEN WATERS OF THE GLFMEX
WITH TYPICAL AFTERNOON SHOWERS/TSTMS EXPECTED OVER FLORIDA.
HURRICANE EMILY IS FORECAST TO MOVE ACROSS THE YUCATAN PENINSULA
SUN AND ENTER THE GULF OF MEXICO ON MON.

CARIBBEAN SEA...
HURRICANE EMILY DOMINATES THE WEATHER OVER THE CENTRAL AND W
CARIBBEAN SEA WITH ASSOCIATED RAINBANDS EXTENDING OUTWARD UP TO
250 NM TO THE N OF THE CENTER.  AN AREA OF SCATTERED
SHOWERS/TSTMS IS ALSO NOTED FURTHER W OVER THE GULF OF HONDURAS
AND CENTRAL AMERICA BETWEEN NICARAGUA AND GUATEMALA.  THIS
ACTIVITY IS IN ASSOCIATION WITH AN UPPER LOW OVER THE YUCATAN
PENINSULA.  THE UPPER LOW WAS IMPARTING SOME SHEAR OVER EMILY
YESTERDAY BUT HAS SINCE MOVED WESTWARD RELAXING THE SHEAR AND
ALLOWING IMPROVED POLEWARD OUTFLOW.  THE UPPER LOW IS FORECAST
TO CONTINUE MOVING WESTWARD AND WEAKENING.  E OF EMILY...UPPER
LEVEL CONFLUENCE/SUBSIDENCE AND RELATIVELY DRIER AIR ALOFT IS
BEGINNING TO MOVE INTO THE E CARIBBEAN COURTESY OF A
RETROGRADING UPPER LOW OVER THE CENTRAL ATLC.  THIS AIRMASS IS
EXPECTED TO CONTINUE SPREADING WESTWARD OVER THE E CARIBBEAN
PRODUCING MORE STABLE CONDITIONS.

ATLANTIC OCEAN...
THE UPPER LEVEL PATTERN OVER THE ATLC FEATURES WEAK MIDDLE TO
UPPER LEVEL RIDGING OVER THE W ATLC...THE MID-OCEANIC TROUGH
FROM 35N49W TO AN UPPER LOW NEAR 21N55W TO THE COAST OF S
AMERICA NEAR GUYANA...AND E/W ORIENTED RIDGING OVER THE E ATLC
ALONG 22N/23N.  THE WEATHER OVER THE W ATLC REMAINS RELATIVELY
TRANQUIL SAVE SOME WIDELY SCATTERED SHOWERS/TSTMS WITHIN 100 NM
EITHER SIDE OF A LINE FROM THE DOMINICA REPUBLIC TO BERMUDA.
OVER THE CENTRAL ATLC...A HIGH AMPLITUDE TROPICAL WAVE ALONG 52W
CONTINUES TO GENERATE A LARGE AREA OF CLOUDINESS AND
SHOWERS/TSTMS FROM 20N TO 30N BETWEEN 45W-56W.  THE WAVE IS
CURRENTLY EXPERIENCING STRONG SHEAR WHICH IS LIMITING
DEVELOPMENT AND FOCUSING THE STRONGEST SHOWERS/TSTMS N OF 20N. E
OF THE WAVE...A STRONG LOW LEVEL ELY SURGE AND ASSOCIATED
AFRICAN DUST IS OBSERVED MARCHING WESTWARD ACROSS THE E AND
CENTRAL ATLC WITH LEADING EDGE CURRENTLY NEAR 50W.  THE
RELATIVELY DRY/STABLE AIR WITHIN THIS SURGE IS LIMITING DEEP
CONVECTION TO THE ITCZ.

$$
RHOME









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