####018003740####
FXCA20 KWBC 021905

PMDCA 



TROPICAL DISCUSSION - INTERNATIONAL DESKS

NWS WEATHER PREDICTION CENTER COLLEGE PARK MD

304 PM EDT THU MAY 02 2024



WEEKLY DISCUSSION FOR PUERTO RICO AND THE USVI MAY 02/12UTC: A WET

PATTERN IS EXPECTED OVER PR/USVI OVER THE NEXT SEVERAL DAYS. THERE

IS A GOOD CHANCE OF THUNDERSTORMS LATE THIS WEEK INTO THE

WEEKEND...WITH SOME OF THE THUNDERSTORMS WITH THE POTENTIAL OF

BEING STRONG. THE OVERALL MOISTURE WILL BE FROM NORMAL TO ABOVE

NORMAL FOR THE NEXT SEVERAL DAYS...WITH THE LATEST GUIDANCE

SUGGESTING PRECIPITABLE WATER VALUES BETWEEN 1.9 TO 2.3 INCHES

THROUGH THE NEXT 5 TO 7 DAYS...AND PRECIPITABLE WATER AT 2 INCHES

OR HIGHER STARTING ON FRIDAY EVENING. THE LOW TO MID LEVEL

RELATIVE HUMIDITY IS ALSO FORECAST TO BE ABOVE NORMAL FROM FRIDAY

ONWARD. A MID TO UPPER LEVEL TROUGH IS APPROACHING FROM THE

WEST...AND THE 500MB HEIGHT ANOMALY IS VERY PRONOUNCED OVER

HISPANIOLA INTO THE CENTRAL CARIBBEAN...WHILE IT CAUSES THE 500 MB

TEMPERATURES TO BE NEAR -7C TO -8C ON FRIDAY AND SATURDAY OVER THE

LOCAL ISLANDS. OVER THE NEXT FEW DAYS...THE MID LEVEL TROUGH AXIS

WILL REMAIN OVER THE CENTRAL CARIBBEAN...WHILE THE MID AND UPPER

LEVEL WINDS STRENGTHEN OVER THE NORTHEAST CARIBBEAN...CAUSING

STRONG DIVERGENCE ALOFT FROM FRIDAY INTO THE WEEKEND.  THE

DIVERGENCE ALOFT...COMBINED WITH THE COLDER MID LEVEL TEMPS...AND

THE INCREASE IN MOISTURE AT ALL LEVELS...WILL CAUSE AN ENHANCED

CHANCE OF THUNDERSTORMS FROM FRIDAY INTO THE WEEKEND. THE EGDI

ALGORITHM DOES SUGGEST THE POTENTIAL FOR SCATTERED

THUNDERSTORMS...ESPECIALLY FOR FRIDAY AFTERNOON INTO

SATURDAY...THOUGH IT CONTINUES TO SUGGEST POSSIBLE ISOLATED TO

SCATTERED THUNDERSTORMS INTO NEXT WEEK AS WELL. THAT SAID...THE

GR02T ALGORITHM SUGGESTS A MARGINAL RISK FOR SEVERE THUNDERSTORMS

FROM FRIDAY INTO THIS WEEKEND. THIS IS POSSIBLY DUE TO THE

POSITIONING OF THE MID LEVEL TROUGH AND THE COLD MID LEVEL

TEMPS...HOWEVER...THE MODEL GUIDANCE DOES NOT TAKE THE -8C MID

LEVEL TEMP CONTOUR OVER PR...KEEPING IT TO THE NORTH OF THE LOCAL

ISLANDS...AND THEREFORE NOT SUGGESTING A HIGHER CHANCE OF SEVERE

THUNDERSTORMS AND HAIL POTENTIAL...THOUGH ISOLATED STRONG STORMS

WITH SMALL HAIL WOULD NOT BE RULED OUT AT THIS POINT. THE GR02T

ALGORITHM DOES NOT SUGGEST POTENTIAL FOR STRONG THUNDERSTORMS

AFTER THIS WEEKEND.



AS MENTIONED ABOVE...THE HIGHER THAN NORMAL MOISTURE IS EXPECTED

TO CONTINUE INTO NEXT WEEK. THE GLOBAL AND LONG RANGE MODELS ARE

SUGGESTING A PERSISTENT AND RELATIVELY NARROW LINE OF MOISTURE

OVER THE NORTHEAST CARIBBEAN...ASSOCIATED WITH A FRONTAL BOUNDARY

EXTENDING FROM THE CENTRAL ATLANTIC. A SFC HIGH PRESSURE OVER THE

WEST TROPICAL ATLANTIC WILL ALSO HELP KEEP THE MOISTURE OVER THE

LEEWARD ISLANDS TO THE WEST INTO HISPANIOLA. THERE IS SOME

DISCREPANCIES IN THE WIND FLOW OVER THE NORTHEAST CARIBBEAN AMONG

THE MODEL GUIDANCE IN THE EXTENDED FORECAST...THAT IS FOR NEXT

TUESDAY INTO WEDNESDAY. THE OVERALL WIND FLOW COULD DICTATE WHERE

THE HIGHEST RAINFALL AMOUNTS COULD BE EARLY INTO THE MIDDLE OF

NEXT...BUT BEING THIS FAR INTO THE FORECAST PERIOD...THERE IS

CONSIDERABLE UNCERTAINTY. THAT BEING SAID...BOTH GLOBAL MODELS ARE

IN AGREEMENT THAT HIGH MOISTURE CONTENT WILL BE PRESENT OVER THE

AREA INTO THE MIDDLE OF NEXT WEEK...SO SOME SIGNIFICANT SHOWER

ACTIVITY COULD STILL BE EXPECTED WITH THE DEEP MOISTURE THAT IS

FORECAST. THE IMPACT OF THE RAINFALL EARLY NEXT WEEK COULD BE

SIGNIFICANT...THOUGH STRONG THUNDERSTORMS ARE NOT EXPECTED EARLY

NEXT WEEK...THE SOILS ACROSS SOME AREAS OF PR/USVI COULD BE

SATURATED BY THEN...CONSIDERING WHAT IS EXPECTED THIS WEEKEND.



ALAMO...WPC (USA)





$$





####018006051####
FXUS21 KWNC 021905

PMDTHR

US Hazards Outlook

NWS Climate Prediction Center College Park MD

300 PM EDT May 02 2024



SYNOPSIS: Mid-level high pressure is forecast to linger from the end of week-1 

into the beginning of week-2 over the south-central and southeastern CONUS, 

weakening significantly by the middle of the period. This may increase chances 

for excessive heat hanging around the Gulf Coast states and South Carolina, 

albeit a more scoped area across the south compared to yesterday. Passage of a 

front may bring heavy rain to parts of the Lower Mississippi and Tennessee 

Valleys, and Southern Appalachians at the start of the period. Surface lows 

predicted over the Four Corners may support periods of high winds across parts 

of the Four Corners and Southern Plains. Dry soils combined with little 

anticipated precipitation during weeks 1 and 2 supports the potential for rapid 

onset drought across parts of the Florida peninsula.



HAZARDS



Moderate risk of excessive heat for parts of the Gulf Coast states and South 

Carolina, Fri, May 10.



Slight risk of excessive heat for parts of the Gulf Coast states and South 

Carolina, Fri-Sat, May 10-11.



Slight risk of heavy precipitation across parts of the Lower Mississippi and 

Tennessee Valleys, and Southern Appalachians, Fri-Sat, May 10-11.



Slight risk of episodes of high winds for parts of the Four Corners and 

Southern Plains, Fri-Sun, May 10-12.



Rapid onset drought risk over parts of the Florida Peninsula.



DETAILED SUMMARY



FOR SUNDAY MAY 05 - THURSDAY MAY 09: 

https://www.wpc.ncep.noaa.gov/threats/threats.php



FOR FRIDAY MAY 10 - THURSDAY MAY 16: The 0Z GEFS, ECENS, and Canadian ensemble 

means are in good agreement today indicating mid-level ridging lingering from 

the end of week-1 into the beginning of week-2 across the south-central and 

southeastern CONUS before weakening.The slight risk of excessive heat has been 

decreased in coverage and time across parts of the Gulf Coast states and South 

Carolina, May 10 to 11, where the GEFS and ECENS probabilistic extremes tools 

(PETs) show at least a 20% chance of maximum temperatures exceeding the 85th 

percentile, climatologically, and 90 Deg F (100 Deg F across southwestern 

Texas). An embedded area is designated with a moderate risk (40 to 60% chance) 

for day 8 only (May10) where the ECENS (GEFS) PET shows at least a 50% (40%) 

chance of maximum temperatures exceeding the 85th percentile across much of the 

moderate risk area. The National Blend of Models (NBM) shows relatively 

widespread potential for record high temperatures, May 9th, in the low to mid 

90s across the Lower Mississippi Valley and Florida, with triple digits (deg F) 

across southwestern Texas.







Multiple models show the potential of a front extending from the Northeast to 

Southern Plains at the beginning of the period, which could bring enhanced 

rainfall to parts of the southeastern CONUS. There is significant uncertainty 

regarding the specific areas that would get the heaviest precipitation, with 

this front expected to be fairly progressive and heavy precipitation to be 

relatively localized. A general area of slight risk is designated across parts 

of the Lower Mississippi and Tennessee Valleys, and Southern Appalachians, May 

10-11, primarily based on where the ECENS (GEFS) PET shows at least a 20% (30%) 

chance of 3-day (day 8-10) rainfall totals exceeding the 85th percentile and 

one inch (0.75 inches), and uncalibrated totals. Due to decreasing wet signals 

during week-1 and week-2, the NWC does not have a possible flood risk during 

the 4 to 7 day period, thus the flood risk is discontinued in today’s outlook.







A series of surface lows are anticipated to form over the southwestern CONUS at 

the beginning of week-2. These disturbances combined with adjacent surface high 

pressure over the North Pacific supports areas of tight pressure gradients and 

resultant increased chances for high winds across the southwestern CONUS. A 

slight risk of episodic high winds is continued across parts of the Four 

Corners and Southern Plains, May 10-12 based on where both the GEFS and ECENS 

PETs shows at least a 20% chance of wind speeds exceeding the 85th percentile 

and 20 mph across the highlighted risk area in addition to where recent 

deterministic model runs indicate enhanced wind speeds and surface low 

formation. Anticipated increased potential for high winds combined with dry 

soils and antecedent and expected dry conditions supports enhanced risk for 

wildfires, especially across the Big Bend of Texas, New Mexico, and Arizona, 

where the National Interagency Fire Center (NIFC) shows moderate risk of 

significant fire potential by the end of week-1.







Above-normal temperatures and near- to below-normal precipitation is forecast 

during weeks 1 and  2 across the central Florida peninsula. Additionally, soil 

moisture levels are declining due to limited precipitation in recent weeks and 

months. Recent weeks have seen areas of abnormal dryness (D0) developing and 

expanding. Increasing sun angle and temperatures in the 80-90 deg F could lead 

to further drying of soils and potentially lead to drought conditions across 

this region. Therefore, an area of rapid onset drought (ROD) is posted for 

portions of central Florida, where severe drought is not already occurring.







In Alaska, snowmelt season is underway and frozen rivers are beginning to break 

up. Currently there are limited areas in flood watch, although there could be 

increased potential for river flooding related to ice-jams over the next couple 

weeks. We continue to monitor the situation but currently there are no 

indications of impending major river flooding related to ice break-ups so no 

flooding-related hazards are posted at this time.



FORECASTER: Melissa Ou 



$$