[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAY 24 2014

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLC WITH AXIS
EXTENDING NEAR 35W-36W. WITHIN THE LAST 24 HOURS THIS WAVE HAS
BEEN MOVING WESTWARD AT 20-25 KT WHILE THE LOW LEVEL CYCLONIC
CIRCULATION ASSOCIATED WITH IT HAS VANISHED. CURRENTLY...THE
WAVE SIGNAL IN MODEL GUIDANCE AT 700 HPA IS VERY WEAK...HOWEVER
THE GUIDANCE SHOWS THE WAVE WILL AMPLIFY BY MONDAY AND BE JUST
EAST OF THE LESSER ANTILLES BY WEDNESDAY. THE WAVE CONTINUES
EMBEDDED WITHIN THE ITCZ AXIS WHICH MAY BE MASKING ITS SIGNAL AT
THE TIME. SCATTERED MODERATE CONVECTION IS WITHIN THE WAVE
ENVIRONMENT FROM 1S-8N BETWEEN 32W-42W.

A SECOND TROPICAL WAVE IS SE OF THE LESSER ANTILLES WITH AXIS
NEAR 55W-56W AND MOVING WEST AT 15 KT WITHIN THE LAST 24 HOURS.
MODEL GUIDANCE SHOW A CLEAR SIGNAL OF THIS WAVE AT THE 700 HPA
AND INDICATES IT WILL BE MOVING ACROSS THE WINDWARD ISLANDS BY
MONDAY MORNING BRINGING RAINSHOWERS TO THIS REGION.
CURRENTLY...THE SSMI TPW IMAGERY SHOW THE WAVE IS EMBEDDED
WITHIN VERY MOIST AIR WHICH ALONG UPPER LEVEL DIFFLUENCE IS
SUPPORTING CLUSTERS OF MODERATE CONVECTION FROM 3N-10N BETWEEN
53W-58W. ISOLATED SHOWERS ARE ELSEWHERE FROM 3N-13N BETWEEN 52W-
60W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST OF GUINEA
NEAR 9N13W AND THEN INTO THE TROPICAL EASTERN ATLC ALONG 7N15W TO
5N18W. THE ITCZ AXIS BEGINS NEAR 5N18W AND CONTINUES ALONG 1N27W
TO EAST OF A TROPICAL WAVE NEAR 1N35W. IT RESUMES WEST OF THE TROPICAL
WAVE NEAR 1N37W TO 2N45W TO 4N51W. SMALL CLUSTERS OF MODERATE TO
ISOLATED STRONG CONVECTION ARE FROM 1S-6N E OF 30W. SCATTERED
MODERATE CONVECTION IS ELSEWHERE FROM 1S-8N W OF 30W.

...DISCUSSION...

GULF OF MEXICO...
MIDDLE TO UPPER LEVEL RIDGING REMAINS ACROSS THE GULF AND
CONTINUE TO SUPPORT A SURFACE RIDGE ANCHORED BY A 1019 MB HIGH
NEAR 29N88W. THIS IS MAINTAINING ANTICYCLONIC WIND FLOW OF 5-15
KT ACROSS THE GULF. SSMI TPW IMAGERY SHOW VERY MOIST AIR IN THE
FAR WESTERN BASIN BEING ADVECTED FROM THE NW CARIBBEAN BASIN
WHILE DRY AIR DOMINATES ELSEWHERE. ALOFT...WATER VAPOR IMAGERY
SHOW A SWATH OF MOIST AIR ACROSS THE GULF BEING ADVECTED FROM
THE EPAC BY SW WIND FLOW. HOWEVER...STRONG DEEP LAYER WIND SHEAR
ACROSS THE BASIN IS SUPPORTING FAIR WEATHER. THE HIGH PRESSURE
CENTER IS FORECAST TO DISSIPATE BY SUNDAY NIGHT. HOWEVER...A
BROAD AREA OF HIGH PRESSURE COMING OFF THE CAROLINAS COAST THE
SAME DAY WILL SUPPORT RIDGING AND RETURN FLOW ACROSS THE BASIN
THROUGH TUESDAY NIGHT. OTHERWISE...A FRONTAL SYSTEM CURRENTLY
ACROSS GEORGIA IS EXPECTED TO REACH THE NORTHERN FLORIDA
PENINSULA AND NE GULF ADJACENT WATERS BY SUNDAY MORNING
ENHANCING RAINSHOWERS THROUGH THE NIGHT.

CARIBBEAN SEA...
A DEEP LAYER TROUGH DOMINATES ACROSS THE CARIBBEAN WATERS WHICH
IS SUPPORTING A SURFACE TROUGH ANALYZED FROM EASTERN CUBA NEAR
20N76W TO SOUTHERN ADJACENT WATERS OF JAMAICA NEAR 16N78W. WITH
MODERATE MOISTURE MAINLY ACROSS THE NW CARIBBEAN AND THE TROUGH
ALOFT SUPPORTING LIFTING...SCATTERED SHOWERS AND TSTMS ARE BEING
ENHANCED ACROSS CUBA AND JAMAICA WHILE ISOLATED SHOWERS AND
TSTMS AFFECT HISPANIOLA. PASSING SCATTERED SHOWERS ARE POSSIBLE
FOR PUERTO RICO AND ADJACENT WATERS TONIGHT. ISOLATED SHOWERS
AND TSTMS ASSOCIATED WITH THE MONSOON TROUGH ARE NOTED IN THE SW
BASIN S OF 11N BETWEEN 76W-82W. ELSEWHERE...DEEP LAYER DRY AIR
SUPPORTS FAIR WEATHER. THE AZORES HIGH EXTENDS A RIDGE SW TO THE
NORTHERN BASIN WHICH IS TIGHTENING THE PRESSURE GRADIENT TO
SUPPORT TRADES OF 20-25 KT ACROSS THE CENTRAL CARIBBEAN S OF
17N. A MORE RELAXED PRESSURE GRADIENT ELSEWHERE SUPPORT TRADES
OF 15 KT. A TROPICAL WAVE IS FORECAST TO MOVE ACROSS THE
WINDWARD ISLANDS BY MONDAY MORNING ENHANCING SHOWERS IN THIS
REGION.

...HISPANIOLA...
THE SURFACE TROUGH THAT WAS MOVING ACROSS THE ISLAND EARLIER
THIS MORNING IS NOW ACROSS EASTERN CUBA AND JAMAICA...HOWEVER A
DEEP LAYER TROUGH ACROSS THE CARIBBEAN AND THE AVAILABILITY OF
MODERATE MOISTURE ACROSS THE ISLAND IS SUPPORTING SCATTERED
SHOWERS WITH ISOLATED TSTMS NOTED OVER THE NORTH-CENTRAL ISLAND.
THIS ACTIVITY WILL REDUCE OVER THE REMAINDER WEEKEND AS A DRY
AIRMASS OVER THE EASTERN CARIBBEAN MOVES ACROSS THE REGION.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH COVERS THE WESTERN ATLC WHICH IS SUPPORTING
A FRONTAL SYSTEM N OF THE AREA. A COLD FRONT ASSOCIATED WITH
THIS SYSTEM WILL ENTER THE SW N ATLC BY SUNDAY MORNING AND WILL
KEEP MOVING SLOWLY ACROSS THE REGION THROUGH TUESDAY MORNING. A
BROAD UPPER LEVEL RIDGE THAT COVERS THE CENTRAL AND PARTS OF THE
EASTERN ATLC IS GENERATING DIFFLUENCE ALOFT TO SUPPORT SCATTERED
SHOWERS AND TSTMS N OF 26N BETWEEN 58W-63W AND ISOLATED SHOWERS
NE OF PUERTO RICO. OTHERWISE...EXCEPT FOR THE TROPICAL WAVES
DISCUSSED ABOVE...SURFACE RIDGING AND FAIR WEATHER DOMINATE
ELSEWHERE.

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

$$
NR


This weather bulletin was brought to you by:
www.nashvilleweather.net