033
FXUS02 KWBC 121857
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
257 PM EDT WED JUN 12 2024
VALID 12Z SAT JUN 15 2024 - 12Z WED JUN 19 2024
...EARLY SEASON HEATWAVE EXPECTED FROM THE CENTRAL PLAINS TO THE
EAST COAST WITH WIDESPREAD HIGHS IN THE 90S...
...GRADUALLY IMPROVING CONDITIONS FOR FLORIDA WHILE WESTERN GULF
BECOMES MORE ACTIVE EARLY NEXT WEEK...
..GENERAL OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
GUIDANCE GENERALLY REMAINS IN GOOD OVERALL AGREEMENT INTO NEXT
WEEK WITH RESPECT TO THE OVERALL PATTERN, FEATURING A BUILDING
UPPER RIDGE ACROSS THE EASTERN HALF OF THE U.S., AND A DEVELOPING
TROUGH OVER THE INTERMOUNTAIN WEST. THE GUIDANCE INDICATES A
SOUTHERN STREAM SHORTWAVE OVER THE SOUTHWEST WILL LIFT NORTHEAST,
AND AROUND THE WESTERN PERIPHERY OF THE BUILDING RIDGE WITH
ADDITIONAL EMBEDDED WAVES CROSSING THE NORTHERN TIER AS THE MAIN
UPPER TROUGH BEGINS TO TAKE HOLD OVER THE WEST. AN UPPER-LEVEL
DISTURBANCE OVER FLORIDA THIS WEEK WILL SLOWLY RETROGRADE OVER THE
GULF OF MEXICO THIS WEEKEND INTO NEXT WEEK. THIS WILL BRING
GRADUALLY IMPROVING CONDITIONS FOR FLORIDA, WHILE INCREASING
RAINFALL CHANCES FOR THE CENTRAL AND WESTERN GULF COAST GOING INTO
SUNDAY AND EARLY NEXT WEEK
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A
MULTI-DETERMINISTIC MODEL BLEND FOR THE WEEKEND, ALONG WITH SOME
PREVIOUS WPC CONTINUITY. THERE IS A GRADUAL INCREASE OF THE
GEFS/ECMWF ENSEMBLE MEANS THROUGH NEXT WEDNESDAY TO ACCOUNT FOR 40%
OF THE BLEND AMID GROWING FORECAST MODEL DIFFERENCES TYPICAL AT
THIS TIME RANGE.
..WEATHER/HAZARDS HIGHLIGHTS
THE COVERAGE OF HEAVY SHOWERS AND STORMS OVER THE CENTRAL AND
SOUTHERN FLORIDA PENINSULA IS FORECAST TO DECREASE GOING INTO THIS
WEEKEND, AS THE MAIN AXIS OF TROPICAL MOISTURE IS FORECAST TO
DRIFT WESTWARD ACROSS THE GULF OF MEXICO AND THEN AFFECT THE WESTERN
GULF COAST REGION. A DAY4/SATURDAY ERO MARGINAL RISK REMAINS VALID FOR
LINGERING CONVECTIVE ACTIVITY OVER THE SOUTHERN HALF OF FLORIDA.
HOWEVER, AS THE WEEKEND PROGRESSES AND INTO EARLY NEXT WEEK, THERE
IS SOME MODEL GUIDANCE SIGNAL THAT MOISTURE INFLUX AND POSSIBLE
HEAVY RAINFALL MAY REFOCUS AND INCREASE NEAR THE CENTRAL GULF COAST
AND VICINITY. A DAY 5/SUNDAY MARGINAL RISK ERO REMAINS VALID GIVEN
THE MOIST PATTERN. UNCERTAINTY REMAINS, PARTICULARLY WITH THE
POTENTIAL AMOUNT OF RAINFALL AND WITH WESTWARD EXTENT INTO THE
WESTERN GULF THROUGH EARLY-MID NEXT WEEK.
ELSEWHERE, A CONVECTIVE PRECIPITATION EVENT IS LIKELY ACROSS THE
NORTHERN PLAINS AND THEN THE UPPER MIDWEST/WESTERN GREAT LAKES THIS
WEEKEND AS SOUTHERN STREAM TROUGHING EJECTS NORTHEASTWARD TOWARD
THE REGION FROM THE SOUTHWEST, WITH AN MCS LIKELY TO DEVELOP. A
SLIGHT RISK IS NOW PLANNED FOR PORTIONS OF SOUTHERN MINNESOTA,
NORTHERN IOWA, AND WESTERN WISCONSIN TO ACCOUNT FOR THE IMPROVED
MODEL SIGNAL FOR AN AXIS OF 1-3 INCH TOTALS, WITH LOCALLY HIGHER
VALUES POSSIBLE, WHERE SOME CONVECTIVE TRAINING COULD DEVELOP. A
BROADER MARGINAL RISK AREA REMAINS ACROSS MUCH OF THIS SAME REGION
GOING INTO THE DAY 5 PERIOD AS THE OVERALL WEATHER PATTERN DOESN'T
CHANGE ALL THAT MUCH.
AS FOR ANOMALOUS TEMPERATURES, AN AMPLIFIED UPPER RIDGE SLATED TO
STEADILY/BROADLY SHIFT FROM THE SOUTHWEST THROUGH THE SOUTH-
CENTRAL U.S. TO THE EAST OVER THE COMING WEEK WILL PRODUCE
WIDESPREAD ANOMALOUS HEAT AND HUMIDITY, WITH THE POTENTIAL FOR SOME
DAILY RECORD HIGHS TO BE ESTABLISHED. TEMPERATURES WILL ALREADY BE
RATHER HOT OVER PORTIONS OF THE SOUTH BEFORE THE EVEN BROADER
REGION OF HEAT EXPANDS INTO THE MIDWEST/OHIO VALLEY THEN MID-
ATLANTIC/NORTHEAST INTO NEXT WEEK AS THE UPPER-LEVEL RIDGING
BUILDS IN. HIGHS ARE FORECAST WELL INTO THE 90S, POTENTIALLY NEAR
100 DEGREES FOR SOME AREAS, AND WITH LOWS IN THE MIDDLE 60S TO
MIDDLE 70S PROVIDING LITTLE RELIEF FROM THE HEAT OVERNIGHT. THE
CLIMATE PREDICTION CENTER CONTINUES A HEAT THREAT INTO WEEK 2.
SCHICHTEL/HAMRICK
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC MEDIUM
RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION FORECAST (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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