915
FXCA20 KWBC 261919
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
319 PM EDT TUE MAY 26 2026
FORECAST BULLETIN 26 MAY 2026 AT 1915 UTC:
ACROSS CENTRAL AMERICA AND THE YUCATAN PENINSULA...
A SHORTWAVE TROUGH IS CURRENTLY SITUATED OVER THE YUCATAN
PENINSULA, SUPPORTING THE LOWERING OF PRESSURE VALUES AND THE
FORMATION OF LOW LEVEL TROUGHS IN THE REGION. MEANWHILE, ITS BASE
WILL EXTEND INTO HONDURAS. DURING THE DAY ON TUESDAY, EXPECT THE
INTENSIFICATION OF UPPER LEVEL WIND SPEEDS ACROSS HONDURAS AND
NICARAGUA, LEADING TO THE SUSTENANCE OF SPEED DIVERGENCE AND
DIFFLUENCE OFF THE NORTH CARIBBEAN COAST. ON WEDNESDAY, SPEED
DIVERGENCE WILL BE MOST FAVORABLE ACROSS HONDURAS AND NORTHERN
NICARAGUA. BY WEDNESDAY, THE AXIS OF A POTENT UPPER TROUGH WILL
ARRIVE INTO THE YUCATAN PENINSULA, AND AGAIN ITS BASE WILL EXTEND
INTO GUATEMALA. THIS WILL REINFORCE SPEED DIVERGENCE AND
DIFFLUENCE FROM THE YUCATAN AND TOWARDS NORTHWEST CUBA.
THIS DYNAMIC UPPER LEVEL PATTERN WILL SUPPORT THE DEVELOPMENT OF
SURFACE TO LOW LEVEL TROUGHS AND THE INCREASE IN MOISTURE IN THE
ENTIRE REGION. ON TUESDAY, THERE WILL BE A WEAK AND TRANSIENT LOW
LEVEL TROUGH ACROSS THE NORTHEASTERN EXTREMITIES OF THE YUCATAN
PENINSULA, WHICH WILL SUPPORT THE ENHANCEMENT IN LOW LEVEL
CYCLONIC ROTATION. THIS FEATURE WILL SUPPORT MODERATE TOTAL
PRECIPITATION MAXIMA. MEANWHILE IN NORTH-CENTRAL GUATEMALA, EXPECT
MODERATE TOTAL PRECIPITATION MAXIMA WITH THE HIGHEST CHANCES FOR
PRECIPITATION OCCURRING IN THE AFTERNOON TO EVENING FOR TUESDAY.
THIS IS DUE TO THE PRESENCE OF SOUTHEASTERLY LOW LEVEL WINDS
INCREASING OROGRAPHIC EFFECTS AND MOISTURE CONVERGENCE.
ON WEDNESDAY, THERE WILL BE A BRIEF RETURN OF AN EASTERLY LOW
LEVEL WIND PATTERN IN BELIZE AND GUATEMALA AS ANOTHER UPPER LEVEL
TROUGH WILL BEGIN TO DIG INTO THE GULF. THERE WILL BE AN
ENHANCEMENT OF UPPER DIVERGENCE IN GUATEMALA, CAMPECHE, TABASCO,
AND CHIAPAS WITH THE ARRIVAL OF THE TROUGH INTO THE REGION. IN THE
MID-LEVELS, THERE WILL BE AMPLIFIED CONVERGENCE, WHICH WILL
FURTHER AMPLIFY MOISTURE CONVERGENCE IN THE AFOREMENTIONED
REGIONS. THESE CONDITIONS WILL FAVOR ENHANCED TOTAL PRECIPITATION
MAXIMA FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING AND THE
RISK FOR THE DEVELOPMENT OF A MESOSCALE CONVECTIVE SYSTEM (MCS).
IN NICARAGUA AND HONDURAS, A TROPICAL WAVE WILL BE MOVING IN AND
LEADING TO THE INCREASE IN EASTERLY LOW LEVEL WINDS AND MOISTURE
ON WEDNESDAY. EXPECT THE INCREASE IN CYCLONIC ROTATION AND
MOISTURE CONVERGENCE WITH THE PASSAGE OF THIS FEATURE. ENHANCED
TOTAL PRECIPITATION MAXIMA IS THUS LIKELY ACROSS THE NORTHERN
CARIBBEAN COAST OF NICARAGUA AND EASTERN COAST OF HONDURAS.
ANOTHER LOW LEVEL TROUGH WILL BE MOVING INTO NICARAGUA AND
HONDURAS FOR THURSDAY. AGAIN SUPPORTING ENHANCED TOTAL
PRECIPITATION MAXIMA IN THE SAME REGION AS THE DAY PRIOR.
MEANWHILE ON THURSDAY IN THE YUCATAN PENINSULA, BELIZE, AND
NORTH-CENTRAL GUATEMALA, EXPECT THE BRIEF DEVELOPMENT OF A LOW
LEVEL TROUGH FOR THE AFTERNOON INTO EVENING, COINCIDING WITH THE
PERIOD OF MAXIMIZED UPPER DIVERGENCE. PRECIPITABLE WATER VALUES
WILL BE SURPASSING 50MM AND MOISTURE CONVERGENCE WILL BE
AMPLIFIED. THESE CONDITIONS WILL FAVOR ELEVATED TOTAL
PRECIPITATION MAXIMA IN THE REGION.
ACROSS THE REST OF MEXICO...
AN UPPER JET STREAK MAX IS CURRENTLY INTENSIFYING ACROSS NORTHWEST
MEXICO AND IT WILL SUPPORT THE AMPLIFICATION OF AN UPPER LEVEL
TROUGH THAT CURRENTLY HAS AN AXIS NEAR 102W. BY WEDNESDAY EVENING,
THE TROUGH BASE WILL BE AS FAR SOUTH AS 19.5N AND WILL EXTEND INTO
17N FOR THURSDAY. AS THE TROUGH BEGINS TO DIG ON TUESDAY, EXPECT
AN INCREASE IN UPPER DIVERGENCE ACROSS NORTHEAST MEXICO. MID-LEVEL
TROUGHING AND A VORTICITY MAXIMA WILL ALSO BE PRESENT IN THIS
REGION AT THE SAME TIME. THIS WILL SUPPORT THE DESTABILIZATION OF
THE ENVIRONMENT AND THE POTENTIAL FOR SEVERE WEATHER. WITH THE
DECREASE IN PRESSURE LEVELS DUE TO THE PRESENCE OF THE DEEPENING
TROUGH, EXPECT AN INCREASE IN SOUTHERLY LOW LEVEL WINDS AND
MOISTURE, LEADING TO AMPLIFIED MOISTURE CONVERGENCE FOR TUESDAY.
ENHANCED TOTAL PRECIPITATION MAXIMA IS LIKELY WITH THESE
CONDITIONS ACROSS NORTHWEST MEXICO. BY WEDNESDAY, THERE WILL BE A
GRADUAL DECREASE IN PRECIPITATION MAXIMA AS THE TROUGH AXIS
CONTINUES MOVING EASTWARD. ON THURSDAY, THE UPPER TROUGH WILL
PRIMARILY INFLUENCE THE PRECIPITATION REGIME ACROSS YUCATAN, AS
PREVIOUSLY DISCUSSED.
IN CENTRAL MEXICO, EXPECT THE SUSTENANCE OF UPPER DIVERGENCE IN
THE REGION AS DIFFLUENCE WILL BE PREVALENT ALONG THE ENTRANCE AND
BASE REGION OF THE AFOREMENTIONED UPPER TROUGH, ESPECIALLY FOR
WEDNESDAY AND THURSDAY. AS THE TROUGH BEGINS TO EXIT THE COUNTRY
ON THURSDAY, AN UPPER RIDGE WILL MOVE INTO WEST MEXICO AND AGAIN
SUPPORT DIFFLUENCE, AND THUS DIVERGENCE, IN CENTRAL MEXICO. AT THE
LOW LEVELS, THERE WILL BE AN INCREASE IN EASTERLY LOW LEVEL WINDS
INTO THE SOUTH-CENTRAL PACIFIC COAST OF THE COUNTRY, ENABLING THE
TRANSPORT OF MOIST TROPICAL AIR INTO THE INTERIOR OF THE COUNTRY.
THESE CONDITIONS WILL YIELD MODERATE TOTAL PRECIPITATION MAXIMA
FOR THE PACIFIC COASTS OF GUERRERO AND OAXACA AND ACROSS CENTRAL
MEXICO.
ACROSS THE REST OF CENTRAL AMERICA, THE CARIBBEAN, AND SOUTH
AMERICA...
A CONVECTIVE COUPLED KELVIN WAVE IS CURRENTLY MOVING ACROSS THE
BASIN, LEADING TO THE ENHANCEMENT IN UPPER DIVERGENCE ACROSS THE
ENTIRE REGION. CURRENTLY, THERE IS AN UPPER RIDGE SITUATED ACROSS
THE CARIBBEAN SEA THAT WILL CONTINUE TO PROMOTE UPPER DIVERGENCE
IN THE REGION FOR THE NEXT THREE DAYS. MEANWHILE, AN UPPER TROUGH
IS CURRENTLY SITUATED OVER THE EASTERN GREATER ANTILLES, BUT ITS
IMPACTS WILL BE LIMITED TO HISPANIOLA WITH RESPECT TO THE
INTERMITTENT SUSTENANCE OF UPPER DIVERGENCE FOR THE NEXT THREE
DAYS. AT THE SAME TIME, A SERIES OF LOW LEVEL TROUGHS AND
TROPICAL WAVES WILL BE MOVING ACROSS THE BASIN. THE FIRST TROPICAL
WAVE OF INTEREST IS CURRENTLY MOVING ACROSS VENEZUELA AND IS
EXPECTED TO MOVE WEST OF THE ANDES BY TUESDAY EVENING. AS THIS
WAVE CONTINUES TO MOVE ACROSS THE SOUTH CARIBBEAN, EXPECT THE
INCREASE IN MOISTURE IN THE REGION AND THE ENHANCEMENT IN CYCLONIC
ROTATION. THIS FEATURE WILL SUPPORT ENHANCED TOTAL PRECIPITATION
MAXIMA WITH ITS PASSAGE. IT WILL ALSO SUPPORT THE REACTIVATION OF
THE PANAMANIAN TROUGH, ESPECIALLY FOR WEDNESDAY AND THURSDAY.
ELSEWHERE IN THIS REGION, EXPECT THE PRESENCE OF THE INTERTROPICAL
CONVERGENCE ZONE (ITZC) AND MONSOON TROUGH TO CONTINUE TO SUPPORT
DAILY CONVECTION AND SHOWERS, WHERE DAILY LIGHT TO MODERATE
PRECIPITATION ACCUMULATIONS ARE LIKELY. IN THE CARIBBEAN, EXPECT
THE DAILY PASSAGE OF MOISTURE PLUMES THAT WILL SUPPORT DIURNAL
SHOWERS AND THUNDERSTORMS. LIGHT TO MODERATE DAILY ACCUMULATIONS
ARE ALSO LIKELY WITH THESE FEATURES. OTHERWISE, SEASONAL
CONDITIONS WILL PREVAIL ACROSS THE REST OF THE REGION.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYP SOF INIT 27/00 27/12 28/00 28/12 29/00 29/12 30/00 30/12
TW 04N 49W 52W 54W 57W 60W 63W 66W 68W 71W
TW 16N 74W 76W 79W 82W 84W 86W 88W DISS DISS
TW 11N 90W 92W 95W 97W 98W 100W 101W --- ---
TW 09N 99W 101W 103W 105W 108W 110W 111W --- ---
TINOCO-MORALES..(WPC)
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