459
FXUS01 KWBC 090747
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
247 AM EST TUE JAN 9 2024
VALID 12Z TUE JAN 9 2024 - 12Z THU JAN 11 2024
...MAJOR STORM SYSTEM WILL HAMMER THE EASTERN U.S. WITH WIDESPREAD
HEAVY RAIN, STRONG WINDS, AND SEVERE THUNDERSTORMS ON TUESDAY INTO
EARLY WEDNESDAY...
...UNSETTLED WEATHER CONDITIONS CONTINUE FOR THE WESTERN U.S. WITH
MUCH COLDER TEMPERATURES ARRIVING FOR THE NORTHERN PLAINS...
A VERY POTENT MID-UPPER LEVEL TROUGH OVER THE CENTRAL U.S. IS
BECOMING NEGATIVELY TILTED AND THIS IS ALLOWING FOR RAPID SURFACE
CYCLOGENESIS OVER THE MIDWEST AND OHIO VALLEY ON TUESDAY. THE
RESULT WILL LIKELY BE A SUB-980 MB SURFACE LOW OVER MICHIGAN BY
LATE TUESDAY EVENING/NIGHT, AND THIS LOW WILL CONTINUE LIFTING
TOWARD THE NORTHEAST ACROSS SOUTHERN ONTARIO AND INTO QUEBEC BY
WEDNESDAY AFTERNOON. A STRONG COLD FRONT TRAILING SOUTH FROM THE
PARENT LOW WILL EXIT THE EAST COAST OVERNIGHT TUESDAY ACROSS THE
MID-ATLANTIC AND INTO EARLY WEDNESDAY MORNING FOR THE NORTHEAST
U.S.
WIDESPREAD HAZARDOUS WEATHER IMPACTS ARE EXPECTED FOR THE EASTERN
THIRD OF THE U.S. IN ASSOCIATION WITH THIS LOW PRESSURE SYSTEM,
AND NUMEROUS WARNINGS AND ADVISORIES ARE NOW IN EFFECT FROM THE
LOCAL NWS FORECAST OFFICES. ONE OF THE BIG THINGS MAKING WEATHER
HEADLINES WILL BE THE WIDESPREAD EXPANSE OF HEAVY RAIN CAPABLE OF
PRODUCING FLOODING FROM THE FLORIDA PANHANDLE ALL THE WAY NORTH TO
SOUTHERN MAINE. THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL
NOW HIGHLIGHTED BY THE WEATHER PREDICTION CENTER FOR THE
TUESDAY-TUESDAY NIGHT TIME PERIOD FROM NORTHERN VIRGINIA TO
SOUTHERN NEW ENGLAND, WHERE THE COMBINATION OF 1 TO 3 INCH
RAINFALL TOTALS OVER HIGHLY SATURATED, AND IN SOME CASES SNOW
COVERED GROUND, ALONG WITH SWOLLEN CREEKS AND STREAMS, WILL
ELEVATE THE POTENTIAL FOR FLOODING ACROSS THIS REGION. ANOTHER
MAJOR ISSUE THAT IS QUITE CONCERNING IS THE POWERFUL 850 MB LOW
LEVEL JET THAT WILL BE IN PLACE JUST AHEAD OF THE COLD FRONT AS IT
APPROACHES THE EAST COAST, WITH SOUTHERLY WINDS 75 TO 100 MPH JUST
A FEW THOUSAND FEET ABOVE THE SURFACE. AT THE SURFACE, THIS WILL
LIKELY RESULT IN WIDESPREAD 30-50 MPH WINDS, ESPECIALLY NEAR THE
COAST AND FOR ELEVATED AREAS WHERE GUSTS WILL LIKELY EXCEED 50
MPH. INLAND AREAS THAT HAVE MORE OF A SURFACE TEMPERATURE
INVERSION WILL GET LESS OF THIS WIND ENERGY FROM ALOFT MIXING
DOWN, BUT STILL BREEZY NONETHELESS. THEREFORE, HIGH WIND WARNINGS
ARE IN EFFECT FOR MANY AREAS NEAR THE COAST AND STORM WARNINGS FOR
THE OPEN WATERS, AND POWER OUTAGES ARE A REAL POSSIBILITY. THIS
WILL ALSO CAUSE INSTANCES OF COASTAL FLOODING WHERE STRONG ONSHORE
FLOW PILES UP WATER INTO RIVERS AND BAYS. SEVERE THUNDERSTORMS
ARE ALSO EXPECTED FROM NORTHERN FLORIDA TO THE COASTAL PLAIN OF
THE CAROLINAS, WHERE A FAVORABLE COMBINATION OF KINEMATICS AND
INSTABILITY WILL FUEL INTENSE STORMS CAPABLE OF PRODUCING DAMAGING
WINDS AND TORNADOES.
CONDITIONS SHOULD SLOWLY IMPROVE GOING INTO WEDNESDAY IN THE WAKE
OF THIS INTENSE STORM SYSTEM ACROSS THE EASTERN U.S., ALTHOUGH IT
WILL STILL BE RATHER BREEZY WITH WEST TO NORTHWESTERLY FLOW, AND
SNOW SHOWERS FOR THE WESTERN GREAT LAKES AND THE EASTERN OHIO
VALLEY. A WEAKER LOW PRESSURE SYSTEM APPROACHES THE UPPER MIDWEST
AND GREAT LAKES REGION ON WEDNESDAY INTO THURSDAY MORNING, BUT IT
WILL NOT HAVE MUCH MOISTURE TO WORK WITH, SO MAINLY LIGHT SNOW IS
EXPECTED WITH THAT EVENT.
FOR THE WESTERN U.S., THE WEATHER PATTERN WILL ALSO BE ACTIVE WITH
A STRONG PACIFIC FRONT MOVING INLAND WITH VERY HEAVY SNOW FOR THE
CASCADES AND THEN ACROSS THE NORTHERN ROCKIES WITH SNOW LEVELS
DROPPING OVER TIME. BY WEDNESDAY NIGHT, A SECOND DISTURBANCE
MOVES INLAND ACROSS THE DESERT SOUTHWEST AND THIS BRINGS VALLEY
RAIN AND MOUNTAIN SNOW ACROSS ARIZONA AND NEW MEXICO. MEANWHILE,
AN ARCTIC FRONT DROPS SOUTHWARD FROM CANADA ON WEDNESDAY AND THIS
WILL HERALD THE ARRIVAL OF THE COLDEST TEMPERATURES SO FAR THIS
SEASON FOR THE NORTHERN PLAINS, WITH SUBZERO LOWS BECOMING A
REALITY FOR MONTANA AND NORTH DAKOTA, AND THIS COLD AIRMASS WILL
CONTINUE SETTLING SOUTHWARD THROUGH THE END OF THE WEEK. THE
COMBINATION OF THIS FRONT AND THE STORM SYSTEM FROM THE
SOUTHWESTERN U.S. WILL EVENTUALLY RESULT IN A MUCH LARGER LOW
PRESSURE SYSTEM DEVELOPING OVER THE SOUTHERN PLAINS BY THE END OF
THE WEEK.
HAMRICK
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