232
AXNT20 KNHC 211905
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1815 UTC MON SEP 21 2026
TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA, CENTRAL AMERICA
GULF OF AMERICA, CARIBBEAN SEA, NORTHERN SECTIONS OF SOUTH
AMERICA, AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 31N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY, WEATHER OBSERVATIONS, RADAR AND METEOROLOGICAL ANALYSIS.
BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1700 UTC.
..SPECIAL FEATURES
HEAVY RAINFALL IN CENTRAL AMERICA: A MIDDLE AND UPPER LEVEL TROUGH
CURRENTLY EXTENDS OVER THE NW CARIBBEAN. WARM SEA SURFACE
TEMPERATURES IN THE REGION, AS WELL AS A POTENTIAL CENTRAL
AMERICAN GYRE FORMING OVER THE NEXT SEVERAL DAYS, WILL LEAD TO
ENHANCED MOISTURE FUNNELING INTO CENTRAL AMERICA TO SUPPORT HEAVY
RAINFALL FROM SEPTEMBER 22ND THROUGH THE 25TH. THERE IS STILL
SOME UNCERTAINTY REGARDING THE EXACT LOCATION OF HEAVIEST
RAINFALL, BUT FOR NOW HEAVY RAINFALL LOOKS LIKELY ACROSS PORTIONS
OF COSTA RICA AND PANAMA, AS WELL AS ACROSS SOUTHERN GUATEMALA,
FAR WESTERN HONDURAS, AND FAR NORTHERN EL SALVADOR. HEAVY RAINFALL
IN THESE REGIONS WILL RAISE CONCERNS FOR LIFE-THREATENING FLASH
FLOODING AND LANDSLIDES. PLEASE REFER TO LOCAL WEATHER SERVICES AS
WELL AS THE INTERNATIONAL DESK AT THE WEATHER PREDICTION CENTER
FOR MORE INFORMATION.
..TROPICAL WAVES
AN EASTERN ATLANTIC TROPICAL WAVE HAS ITS AXIS NEAR 30-31W, SOUTH
OF 19N, MOVING WESTWARD AT AROUND 10-15 KT. NO SIGNIFICANT
CONVECTION IS NOTED WITH THIS WAVE.
THE AXIS OF A CENTRAL ATLANTIC TROPICAL WAVE IS ANALYZED FROM
21N43W TO 06N48W, MOVING WESTWARD AT AROUND 10 KT. SCATTERED
MODERATE CONVECTION IS ACTIVE ON THE NORTHERN END OF THE TROPICAL
WAVE FROM 18N TO 22N BETWEEN 41W AND 45W.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH EXTENDS OFF THE COAST OF AFRICA NEAR 14N17W TO
07N35W. THE ITCZ EXTENDS FROM 07N35W TO 04N52W. SCATTERED
MODERATE CONVECTION IS NOTED FROM 06N TO 16N AND EAST OF 25W.
SCATTERED SHOWERS ARE ALSO NOTED ALONG AND WITHIN 100 NM OF THESE
FEATURES W OF 25W.
..GULF OF AMERICA
A VERY WEAK PRESSURE GRADIENT PREVAILS ACROSS THE AREA GENERATING
LIGHT TO GENTLE WINDS AND SLIGHT SEAS ACROSS THE GULF. AN UPPER
LOW CENTERED OVER NORTHERN FLORIDA IS INTERACTING WITH A PAIR OF
SURFACE TROUGHS IN THE EASTERN GULF TO SUPPORT SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS N OF 23N AND E OF 90W. ANOTHER SURFACE
TROUGH EXTENDING INTO THE GULF FROM NE MEXICO IS SUPPORTING
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE W GULF AS
WELL.
FOR THE FORECAST, A VERY WEAK PRESSURE GRADIENT WILL FORCE ONLY
GENTLE TO MODERATE WINDS ACROSS THE GULF THROUGH THU. A VIGOROUS
UPPER- LEVEL LOW WILL PROMOTE SCATTERED SHOWERS AND THUNDERSTORMS
OVER THE SE GULF AND THE STRAITS OF FLORIDA FOR AT LEAST THE NEXT
TWO DAYS. LOOKING AHEAD, A COLD FRONT SHOULD DIP INTO THE NE GULF
THU NIGHT AND FRI WITH FRESH NE TO E WINDS TO FOLLOW ACROSS THE N
GULF.
..CARIBBEAN SEA
THE EASTERN EXTENSION OF THE EAST PACIFIC MONSOON TROUGH EXTENDS
ACROSS THE FAR SW CARIBBEAN, WITH A 1010 MB SURFACE LOW ANALYZED
NEAR 12N81W. THESE FEATURES ARE INTERACTING WITH AN UPPER LEVEL
TROUGH OVER THE GULF OF AMERICA AND NW CARIBBEAN TO SUPPORT
NUMEROUS MODERATE TO STRONG CONVECTION ACROSS THE CARIBBEAN
BETWEEN 75-85W, WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
NOTED ALONG THE COASTS OF HONDURAS, BELIZE AND THE YUCATAN
PENINSULA. OUTSIDE OF CONVECTION, A WEAK PRESSURE PATTERN IS
ACROSS THE BASIN. MODERATE TO FRESH WINDS AND MODERATE SEAS
PREVAIL EAST OF 80W. LIGHT TO GENTLE WINDS AND SLIGHT TO MODERATE
SEAS PREVAIL WEST OF 80W.
FOR THE FORECAST, A WEAK PRESSURE GRADIENT BETWEEN HIGH PRESSURE
NORTH OF THE AREA TO THE COLOMBIAN LOW IS FORCING ONLY MODERATE TO
FRESH TRADES OVER THE S CENTRAL CARIBBEAN FOR THE NEXT SEVERAL
DAYS. A VIGOROUS UPPER-LEVEL LOW IS FORCING SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS OVER THE W CARIBBEAN FOR AT LEAST THE
NEXT TWO DAYS.
..ATLANTIC OCEAN
FOR AWARENESS, TROPICAL STORM FAY IS CENTERED NEAR 33.3N 32.0W AT
21/1500 UTC OR 370 NM SW OF THE AZORES, MOVING S AT 4 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED
WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. PLEASE VISIT
HURRICANES.GOV FOR MORE INFO ON TROPICAL STORM FAY.
AN UPPER TROUGH REACHES FROM THE EASTERN GULF INTO THE NORTHWEST
CARIBBEAN. DIVERGENT FLOW ALOFT ON THE EAST SIDE OF THE UPPER
TROUGH IS SUPPORTING CLUSTERS OF SHOWERS AND THUNDERSTORMS ACROSS
A LARGE AREA N OF 20N AND W OF 67W. FARTHER EASTWARD IN THE
CENTRAL ATLANTIC, AN UPPER LEVEL LOW NEAR 26N48W AND SURFACE
TROUGH EXTENDING FROM 32N41W TO 22N55W ARE INTERACTING WITH THE
CENTRAL ATLANTIC TROPICAL WAVE TO SUPPORT SCATTERED MODERATE
CONVECTION FROM 20N TO 31N BETWEEN 36W AND 45W, AS WELL AS MORE
SCATTERED SHOWERS ALONG AND NEAR THE SURFACE TROUGH. OUTSIDE OF
CONVECTION, A VERY WEAK PRESSURE GRADIENT ACROSS MUCH OF THE
ATLANTIC SUPPORTS GENTLE TO MODERATE TRADES AND 3-6 FT SEAS ACROSS
MUCH OF THE BASIN.
FOR THE FORECAST WEST OF 55W, A VERY WEAK PRESSURE GRADIENT
BETWEEN THE BERMUDA- AZORES HIGH AND LOWER PRESSURE OVER THE ITCZ
IS PROMOTING ONLY GENTLE TO MODERATE TRADES ACROSS FORECAST WATERS
THROUGH THU. A VIGOROUS UPPER-LEVEL LOW WILL CONTINUE TO PRODUCE
SCATTERED SHOWERS AND THUNDERSTORMS WEST OF 65W FOR AT LEAST THE
NEXT COUPLE OF DAYS. LOOKING AHEAD, A COLD FRONT WILL EMERGE FROM
THE SE UNITED STATES COAST LATE WED NIGHT AND EXTEND FROM 31N71W
TO THE CENTRAL BAHAMAS FRI MORNING. FRESH N WINDS AND INCREASING
SEAS WILL FOLLOW THE FRONT.
ADAMS
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