719
FXUS02 KWBC 062012
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
412 PM EDT TUE OCT 6 2026
VALID 12Z FRI OCT 09 2026 - 12Z TUE OCT 13 2026
...MONITORING THE TROPICS WITH CONCERNS FOR HEAVY RAINFALL AND
FLASH FLOODING ACROSS PARTS OF THE GULF COAST AND SOUTHEAST LATE
WEEK INTO THE WEEKEND...
..PATTERN OVERVIEW
A TROPICAL SYSTEM IS LIKELY TO BRING THREATS OF HEAVY RAINFALL AND
FLASH FLOODING TO PARTS OF THE GULF COAST AND SOUTHEAST BEGINNING
LATER THIS WEEK AND LASTING THROUGH THE WEEKEND. THE REMNANTS OF
WHAT IS NOW HURRICANE RACHEL MAY ALSO BRING ENHANCED TROPICAL
MOISTURE TO PARTS OF THE SOUTHWEST LATE THIS WEEKEND INTO EARLY
NEXT WEEK, LEADING TO ADDITIONAL HEAVY RAIN AND FLOODING CONCERNS.
MEANWHILE, THE FIRST TASTE OF WINTER IS LIKELY THIS WEEKEND AS
WIDESPREAD ACCUMULATING SNOWFALL IS LIKELY ACROSS THE HIGHER
ELEVATIONS OF THE NORTHERN ROCKIES.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST AVAILABLE GUIDANCE HAS A REASONABLE HANDLE ON THE LARGE
SCALE PATTERN THROUGH MOST OF THE MEDIUM RANGE PERIOD, THOUGH
UNCERTAINTY INCREASES SIGNIFICANTLY LATE THIS WEEKEND INTO EARLY
NEXT WEEK. THE OVERALL PATTERN FEATURES INITIALLY BROAD QUASI-
ZONAL MID-LEVEL FLOW THAT BECOMES INCREASINGLY AMPLIFIED AS
TROUGHING INCREASES ACROSS THE WESTERN U.S. MODELS HAVE BEEN
STRUGGLING WITH HOW TO RESOLVE THE SMALLER SCALE WAVES WITHIN THE
LARGER TROUGHING PATTERN, BUT THE TREND HAS BEEN FOR AMPLIFICATION
TO OCCUR FARTHER WEST (CLOSER TO THE WEST COAST VS INTERMOUNTAIN
WEST) AND THE POTENTIAL FOR A CUT-OFF LOW TO DEVELOP SOMEWHERE OVER
CALIFORNIA. ANOTHER RECENT TREND IS FOR THIS WESTERN TROUGHING TO
MORE DIRECTLY INTERACT WITH WHAT IS NOW HURRICANE RACHEL, STEERING
THE REMNANTS BACK EASTWARD TOWARDS BAJA BEFORE BECOMING ABSORBED
ACROSS THE SOUTHWEST U.S.
IN BETWEEN THE WESTERN TROUGHING AND A STRENGTHENING RIDGE IN THE
SOUTHWEST ATLANTIC OCEAN, A TROPICAL SYSTEM IS LIKELY TO MAKE
LANDFALL SOMEWHERE ALONG THE CENTRAL GULF COAST LATER FRIDAY OR
SATURDAY WITH ITS REMNANTS TRACKING NORTHWARD INTO THE OHIO VALLEY
AND MID-ATLANTIC LATER THIS WEEKEND INTO EARLY NEXT WEEK. TIMING OF
THIS FEATURE CONTINUES TO BE A SOURCE OF UNCERTAINTY WITH
SIGNIFICANT SPREAD NOTED IN VARYING MODELING SUITES. THIS IS LIKELY
DUE TO DIFFERENCES IN SYSTEM STRENGTH AS WELL AS THE DEGREE OF
INTERACTION WITH AN UPPER LOW OVER SOUTHERN TEXAS AND A RIDGE IN
THE SOUTHWEST ATLANTIC. FOR MORE INFORMATION ON THE FUTURE TRACK
AND STRENGTH OF THIS SYSTEM, PLEASE REFER TO THE NATIONAL HURRICANE
CENTER.
..WEATHER/HAZARDS HIGHLIGHTS
THE MAIN WEATHER STORY HEADING INTO THE WEEKEND IS THE INCREASING
POTENTIAL FOR HEAVY RAIN AND FLASH FLOODING FROM THE CENTRAL GULF
COAST TO THE SOUTHEAST AS A TROPICAL SYSTEM LIKELY MAKES LANDFALL
AND TRACKS INLAND. DESPITE UNCERTAINTY IN THE EXACT TRACK, TIMING,
AND STRENGTH OF THIS SYSTEM, RAINFALL WILL POSE A SIGNIFICANT RISK
REGARDLESS OF HOW IT EVOLVES. AS OF RIGHT NOW, THE HEAVIEST RAIN IS
LIKELY TO FALL ON FRIDAY AND SATURDAY, WITH THE HIGHEST TOTALS
STRETCHING FROM EASTERN LOUISIANA TO THE FLORIDA PANHANDLE. THE
LATEST FORECAST DEPICTS STORM TOTAL RAINFALL OF 3-6" WITH LOCALLY
HEAVIER AMOUNTS UP TO 10" AS A REASONABLE WORST CASE SCENARIO.
FORECAST ADJUSTMENTS WILL CONTINUE TO BE MADE OVER THE NEXT SEVERAL
DAYS, SO CONTINUE TO CHECK BACK FOR UPDATES AND REFER TO THE NHC
FOR MORE INFORMATION ON THIS POTENTIAL TROPICAL SYSTEM.
MEANWHILE, THE REMNANTS OF YET ANOTHER TROPICAL SYSTEM WILL HAVE
THE POTENTIAL TO BRING IMPACTS TO THE SOUTHWEST U.S. LATER THIS
WEEKEND INTO EARLY NEXT WEEK. HURRICANE RACHEL IS FORECAST TO
CONTINUE MOVING NORTHWESTWARD IN THE EASTERN PACIFIC BEFORE MAKING
A SHARP TURN TO THE NORTHEAST AS IT WEAKENS. THE REMNANTS OF THIS
SYSTEM WILL THEN BE SWEPT INTO THE SOUTHWEST U.S. AS A DEEPENING
TROUGH TO THE WEST AMPLIFIES. THE TROPICAL MOISTURE ASSOCIATED WITH
THESE REMNANTS WILL INCREASE THE THREAT OF WIDESPREAD HEAVY
RAINFALL AND LOCALIZED FLASH FLOODING ACROSS THE SOUTHWEST AND
INTERMOUNTAIN WEST. SLOT CANYONS, BURN SCARS, AND LOW-LYING, POOR
DRAINAGE AREAS WOULD BE MOST AT RISK.
DESPITE LATE SEASON TROPICAL SYSTEMS AND ABOVE NORMAL WARMTH
ACROSS A LARGE PORTION OF THE COUNTRY, THE FIRST TASTE OF WINTER IS
LIKELY ACROSS THE HIGHER ELEVATIONS OF THE NORTHERN ROCKIES THIS
WEEKEND. A SIGNIFICANT SURGE OF COLD AIR WITH RAPIDLY FALLING SNOW
LEVELS IN THE WAKE OF A COLD FRONT WILL INTERACT WITH ANOMALOUS
MOISTURE TO PRODUCE THE SEASON'S FIRST WIDESPREAD ACCUMULATING
SNOWFALL FOR PARTS OF THE MONTANA, IDAHO, AND WYOMING HIGH COUNTRY.
THE LATEST WSSI-P FEATURES 20 TO 60 PERCENT PROBABILITIES FOR
MINOR WINTER WEATHER IMPACTS, WITH A 10 TO 20 PERCENT CHANCE FOR
MODERATE IMPACTS. A LITTLE SNOW MAY EVEN REACH THE ADJACENT VALLEY
FLOORS, THOUGH ANY ACCUMULATIONS ARE LIKELY TO BE MINIMAL.
MILLER
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, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY MESSAGES
ARE AT:
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page