983
FXUS02 KWBC 110659
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
158 AM EST SUN FEB 11 2024
VALID 12Z WED FEB 14 2024 - 12Z SUN FEB 18 2024
..GENERAL OVERVIEW
A QUASI-ZONAL FLOW PATTERN DEVELOPS ACROSS MUCH OF THE NATION IN
THE WAKE OF THE DEPARTING EAST COAST STORM SYSTEM, AND A PATTERN
CHANGE IS EXPECTED TO EVOLVE BY THURSDAY ACROSS THE NORTH-CENTRAL
U.S. AS AN ARCTIC AIRMASS DROPS SOUTHWARD FROM WESTERN CANADA WITH
A RETURN TO BELOW NORMAL TEMPERATURES. MEANWHILE, A WEAK UPPER
LEVEL RIDGE IS LIKELY TO BECOME ESTABLISHED OVER THE INTERMOUNTAIN
WEST BY THE END OF THE WEEK, AND THIS WILL TEND TO SLOW THE
PROGRESSION OF OFFSHORE PACIFIC STORM SYSTEMS UNTIL ABOUT FRIDAY
WHEN THE NEXT ROUND OF ORGANIZED PRECIPITATION MOVES INLAND ACROSS
CALIFORNIA. ELSEWHERE, SOME LIGHT SNOW SHOWERS ARE POSSIBLE FROM
THE NORTHERN ROCKIES TO THE UPPER MIDWEST WITH WEAK SHORTWAVE
PASSAGES, AND LAKE EFFECT SNOW ACROSS THE GREAT LAKES REGION
FRIDAY NIGHT INTO SATURDAY.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE 00Z MODEL GUIDANCE SUITE IS IN REASONABLY GOOD AGREEMENT
ACROSS THE CONTINENTAL U.S. ON WEDNESDAY, WITH A SLIGHTLY SLOWER
TREND WITH THE LOW EXITING THE EAST COAST. DIFFERENCES BECOME
EVIDENT BY THE END OF THE WEEK WITH THE EXTENT OF THE RIDGE AXIS
ACROSS THE WEST COAST REGION AND THE ARRIVAL OF LEAD PACIFIC
SHORTWAVE ENERGY ACROSS THE WEST COAST REGION. HOWEVER, THERE IS
DECENT MODEL AGREEMENT WITH THE DEVELOPING SOUTHERN STREAM TROUGH
NEAR THE GULF COAST LATE IN THE FORECAST PERIOD. THE USE OF THE
ENSEMBLE MEANS INCREASED TO ABOUT 50 PERCENT BY NEXT WEEKEND TO
ACCOUNT FOR THE GROWING MESOSCALE MODEL DIFFERENCES ELSEWHERE. IN
TERMS OF THE NBM, TEMPERATURES WERE REDUCED BY 2-4 DEGREES ACROSS
MUCH OF THE NORTH-CENTRAL U.S. GIVEN THE STRONGER SIGNAL FOR AN
ARCTIC SURFACE HIGH SETTLING IN FOR THE SECOND HALF OF THE WORK
WEEK. THE QPF WAS ALSO RAISED ACROSS THE GENERAL VICINITY OF THE
GREAT LAKES ON FRIDAY/SATURDAY FROM THE NBM GIVEN THE DECENT
OVERALL SIGNAL FOR A LIGHT TO MODERATE LAKE EFFECT SNOW EVENT.
..OVERVIEW AND WEATHER/HAZARDS HIGHLIGHTS
A RELATIVELY QUIET PERIOD OF TIME IS EXPECTED ACROSS THE NATION ON
WEDNESDAY WITH MOST AREAS REMAINING DRY, AND SOME LIGHT SNOW
ACROSS THE NORTH-CENTRAL U.S. AND THE NORTHERN ROCKIES. THERE
WILL LIKELY BE SOME PACIFIC MOISTURE MOVING INLAND ACROSS THE
PACIFIC NORTHWEST, BUT MODEL GUIDANCE VARIES MORE THAN USUAL FOR
THIS REGION AND OVERALL RAINFALL TOTALS ARE EXPECTED TO BE MODEST.
THEREFORE, NO RISK AREAS ARE WARRANTED FOR THE DAY 4 EXCESSIVE
RAINFALL OUTLOOK ON WEDNESDAY. LOOKING AHEAD TO THURSDAY AND
FRIDAY, A LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP OVER THE
WESTERN GULF AND ADVECT INCREASING MOISTURE NORTHWARD AND OVER A
DEVELOPING WARM FRONT, AND THIS WILL LIKELY RESULT IN WIDESPREAD
SHOWERS AND THUNDERSTORMS ACROSS SOUTHERN TEXAS AND INTO THE
CENTRAL GULF COAST REGION. THE GUIDANCE FAVORS DEEP SOUTH TEXAS
FOR HEAVIEST RAINFALL TOTALS ON THURSDAY, AND A MARGINAL RISK IS
PLANNED FOR THE DAY 5 EXCESSIVE RAINFALL OUTLOOK. MORE HEAVY RAIN
IS LIKELY ACROSS PORTIONS OF THE DEEP SOUTH GOING INTO THE
FRIDAY-SATURDAY TIME PERIOD AS THE SURFACE LOW TRACKS TOWARDS THE
SOUTHEAST U.S. COAST. ADDITIONALLY, THE NEXT ROUND OF ORGANIZED
PACIFIC MOISTURE IS EXPECTED TO REACH THE WEST COAST ON FRIDAY AND
RESULT IN MODERATE TO HEAVY RAIN FOR THE NORTHERN HALF OF
CALIFORNIA, AND SNOW FOR THE HIGHER TERRAIN. FARTHER EAST, THE
PROSPECTS FOR LAKE EFFECT SNOW ARE INCREASING TO CLOSE OUT THE
WORK WEEK WITH THE MUCH COLDER AIRMASS CROSSING THE GREAT LAKES,
WITH THE GREATEST SNOWFALL LIKELY ACROSS CENTRAL AND NORTHERN
MICHIGAN.
TEMPERATURES ARE EXPECTED TO BE GENERALLY 5 TO 15 DEGREES ABOVE
MID-FEBRUARY AVERAGES ACROSS MUCH OF THE MIDWEST REGION ON
WEDNESDAY AND THEN ACROSS HE MID-SOUTH AND OHIO VALLEY REGION ON
THURSDAY. MEANWHILE, A STRONG COLD FRONT DROPPING SOUTH FROM
WESTERN CANADA IS EXPECTED TO HERALD THE ARRIVAL OF AN ARCTIC
AIRMASS ACROSS THE NORTHERN PLAINS AND BRING A RETURN TO BELOW
AVERAGE TEMPERATURES FROM MONTANA TO THE DAKOTAS AND MINNESOTA
THROUGH THE END OF THE WEEK, PERHAPS UP TO 25 DEGREES BELOW
AVERAGE ACROSS PORTIONS OF MONTANA, BUT NOT QUITE AS COLD AS THE
PREVIOUS ARCTIC BLAST BACK IN MID-JANUARY. MEANWHILE, MUCH OF THE
REMAINDER OF THE U.S. SHOULD HAVE TEMPERATURES NEAR OR SLIGHTLY
BELOW CLIMATOLOGICAL AVERAGES GOING INTO NEXT WEEKEND.
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, 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
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