582
FXUS21 KWNC 052140
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 05 2024
SYNOPSIS: A HIGHLY AMPLIFIED MEAN MID-LEVEL PATTERN OVER NORTH AMERICA IS
EXPECTED TO INCREASE THE RISK FOR MANY WEATHER-RELATED HAZARDS THROUGHOUT THE
CONTIGUOUS U.S. (CONUS). SURFACE HIGH PRESSURE FORECAST TO DESCEND FROM
SOUTHERN CANADA SIGNALS THE INCREASED LIKELIHOOD OF AN ARCTIC AIR OUTBREAK OVER
MUCH OF THE WESTERN AND CENTRAL CONUS. ENHANCED ATMOSPHERIC MOISTURE OVER THE
WEST IS EXPECTED TO PROMOTE HIGH ELEVATION SNOWFALL, AND THE POSSIBLE RETURN OF
HEAVY PRECIPITATION ACROSS THE WEST COAST. ANOTHER PREDICTED LOW PRESSURE
SYSTEM MAY LEAD TO HEAVY PRECIPITATION AND EPISODES OF HIGH WINDS ACROSS THE
EASTERN CONUS WITH THE POTENTIAL FOR HEAVY ACCUMULATING SNOW OVER THE MIDWEST,
GREAT LAKES, AND INTERIOR NORTHEAST EARLY IN THE PERIOD.
HAZARDS
HIGH RISK OF MUCH BELOW-NORMAL TEMPERATURES FROM THE PACIFIC NORTHWEST COAST
EASTWARD ACROSS THE NORTHERN ROCKIES, NORTHERN AND CENTRAL PLAINS, AND INTO THE
MID-UPPER MISSISSIPPI VALLEY, SAT-MON, JAN 13-15.
MODERATE RISK OF MUCH BELOW-NORMAL TEMPERATURES EAST-SOUTHEASTWARD FROM
CALIFORNIA ACROSS THE FOUR CORNERS REGION, SOUTHERN ROCKIES, AND SOUTHERN HIGH
PLAINS, SAT-SUN, JAN 13-14.
MODERATE RISK OF MUCH BELOW-NORMAL TEMPERATURES EASTWARD AND SOUTHEASTWARD FROM
THE PACIFIC NORTHWEST ACROSS MOST OF THE ROCKIES, GREAT PLAINS, AND MISSISSIPPI
VALLEY, SAT-TUE, JAN 13-16.
SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR MOST AREAS BETWEEN THE WEST
COAST AND THE APPALACHIANS, SAT-FRI, JAN 13-19.
MODERATE RISK OF HEAVY PRECIPITATION FOR MOST OF CALIFORNIA AND SOUTHWESTERN
OREGON, SAT-FRI, JAN 13-19.
MODERATE RISK OF HEAVY PRECIPITATION ALONG THE EASTERN SEABOARD AND OVER THE
SOUTHEAST, SAT-SUN, JAN 13-14.
SLIGHT RISK OF HEAVY PRECIPITATION FOR MOST OF CALIFORNIA, WESTERN OREGON, AND
SOUTHWESTERN WASHINGTON, SAT-FRI, JAN 13-19.
SLIGHT RISK OF HEAVY PRECIPITATION FROM TENNESSEE AND MISSISSIPPI EASTWARD TO
THE SOUTHEAST COAST, MID-ATLANTIC, AND NORTHEAST, SAT-MON, JAN 13-15.
MODERATE RISK OF HEAVY SNOW FOR THE HIGHER ELEVATIONS OF THE FOUR CORNERS, SAT,
JAN 13.
MODERATE RISK OF HEAVY SNOW FROM EASTERN KANSAS NORTHEASTWARD ACROSS THE UPPER
GREAT LAKES REGION, SAT-MON, JAN 13-15.
MODERATE RISK OF HEAVY SNOW FOR THE SOUTHERN CASCADES, KLAMATH/SISKIYOU AND
SIERRA MOUNTAINS, SAT-FRI, JAN 13-19.
SLIGHT RISK OF HEAVY SNOW FOR THE FOUR CORNERS REGION, SAT-SUN, JAN 13-14.
SLIGHT RISK OF HEAVY SNOW FROM THE SOUTH-CENTRAL PLAINS NORTHEASTWARD ACROSS
MOST OF THE MISSISSIPPI VALLEY AND GREAT LAKES REGION, NORTHERN OHIO VALLEY,
AND INTERIOR NORTHEAST, SAT-MON, JAN 13-15.
SLIGHT RISK OF HEAVY SNOW FOR MOST OF THE CASCADES, KLAMATH/SISKIYOU AND SIERRA
MOUNTAINS, SAT-FRI, JAN 13-19.
SLIGHT RISK OF HEAVY SNOW FOR APPROXIMATELY THE NORTHERN TWO-THIRDS OF THE
ROCKIES AND ADJACENT PORTIONS OF THE INTERMOUNTAIN REGION, SAT-FRI, JAN 13-19.
SLIGHT RISK OF HIGH WINDS FOR MOST OF THE CENTRAL AND EASTERN CONUS, SAT-TUE,
JAN 13-16.
SLIGHT RISK OF HIGH WINDS FOR MANY AREAS WEST OF THE CONTINENTAL DIVIDE,
SAT-MON, JAN 13-15.
POSSIBLE FLOODING FOR MOST OF THE EAST COAST STATES FROM NORTHERN FLORIDA TO
CENTRAL NEW ENGLAND.
DETAILED SUMMARY
FOR MONDAY JANUARY 08 - FRIDAY JANUARY 12:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY JANUARY 13 - FRIDAY JANUARY 19: THE WEEK-2 HAZARDS PERSPECTIVE
MOSTLY REMAINS ON TRACK SINCE YESTERDAY, AS THERE ARE MULTIPLE WEATHER RELATED
HAZARD RISKS ASSOCIATED WITH DEEPLY AMPLIFIED MEAN 500-HPA TROUGHING FEATURED
IN THE DYNAMICAL MODELS OVER MUCH OF THE CONUS. ARCTIC SURFACE HIGH PRESSURE
OVER WESTERN CANADA IS FORECAST TO PUSH SOUTHWARD AND EASTWARD ACROSS MOST OF
THE WESTERN, CENTRAL, AND EAST-CENTRAL CONUS DURING WEEK-2. THE PROBABILISTIC
EXTREMES TOOLS (PETS) FEATURES HIGH (> 60% CHANCE), MODERATE (> 40%), AND
SLIGHT (> 20%) RISKS OF MUCH BELOW-NORMAL TEMPERATURES (MINIMUM TEMPERATURES
FALLING TO WITHIN THE LOWEST 15% OF THE CLIMATOLOGICAL TEMPERATURE
DISTRIBUTION) DURING VARIOUS PORTIONS OF THE FORECAST PERIOD FOR MOST AREAS
WEST OF THE APPALACHIANS. OVERNIGHT TEMPERATURES ARE EXPECTED TO DROP BELOW 20
DEG F FOR MOST OF THE COUNTRY, WITH THE EXCEPTIONS OF THE FAR SOUTHERN TIER AND
COASTAL PORTIONS OF THE WEST. TEMPERATURES ARE FAVORED TO REACH 0 DEG F (OR
LOWER) FOR MUCH OF THE INTERIOR WEST, THE NORTHERN AND CENTRAL PLAINS, THE
MIDWEST, GREAT LAKES, AND INTERIOR NORTHEAST DURING MUCH OF WEEK-2, WITH
ANTICIPATED WIND CHILL VALUES IN THE RANGE OF -20 DEG F TO -40 DEG F.
EVEN THE LOWLANDS OF THE PACIFIC NORTHWEST (E.G. SEATTLE AND PORTLAND) ARE
FAVORED TO HAVE MINIMUM TEMPERATURES FALLING TO 20-25 DEG F AT THE START OF
WEEK-2, WHICH IS 10-15 DEGREES BELOW NORMAL. ACCORDINGLY, A HIGH RISK IS
DESIGNATED FOR MUCH BELOW-NORMAL TEMPERATURES FOR THE COASTAL NORTHWEST FROM
JAN 13-15.
FOR THE PAST SEVERAL DAYS, DYNAMICAL MODEL GUIDANCE HAS TRENDED TOWARD A WETTER
SOLUTION FOR THE WEST COAST STATES. SLIGHT AND MODERATE RISKS OF HEAVY
PRECIPITATION ARE HIGHLIGHTED FOR THE DURATION OF WEEK-2. IN GENERAL, ONE TO
GREATER THAN TWO INCHES OF RAIN CAN BE EXPECTED AT LOWER ELEVATIONS. SLIGHT AND
MODERATE RISKS OF HEAVY SNOW (1-2 FEET OR MORE) ARE ALSO DEPICTED FOR THE
CASCADES, THE KLAMATH/SISKIYOU MOUNTAINS, AND SIERRA NEVADAS FOR THE ENTIRE
FORECAST PERIOD. IT IS IMPORTANT TO NOTE THAT EVEN PLACES A BIT WEST OF THE
HIGHER TERRAIN (SUCH AS PORTLAND OR) MAY RECEIVE ACCUMULATING SNOWFALL DURING
THIS COLD SNAP. FARTHER EAST, ACROSS THE FOUR CORNERS REGION, ROCKIES, AND
ADJACENT EASTERN INTERMOUNTAIN REGION, THERE ARE TWO SLIGHT RISK AREAS FOR
HEAVY SNOW POSTED FOR MOST, IF NOT ALL, OF WEEK-2. IN ADDITION, A MODERATE RISK
FOR HEAVY SNOW CONTINUES ACROSS THE HIGHER ELEVATIONS OF THE FOUR CORNERS
REGION, AT LEAST FOR THE FIRST DAY OF THE PERIOD. WITH THE FAVORED INCREASE IN
STORM ACTIVITY ACROSS THE WEST, A SLIGHT RISK OF HIGH WINDS (20-25 MPH+) IS
POSTED FOR MANY AREAS WEST OF THE CONTINENTAL DIVIDE, JAN 13-15.
IN THE EAST, A STORM SYSTEM NEAR THE ATLANTIC SEABOARD IS PREDICTED TO
GRADUALLY MOVE OFFSHORE DURING THE FIRST FEW DAYS OF WEEK-2. IN ADDITION TO
SLIGHT AND MODERATE RISKS FOR HEAVY PRECIPITATION POSTED OVER THIS REGION,
THERE CONTINUES TO BE AN ELEVATED FLOOD RISK, DUE TO RAIN FALLING ON SNOW AND
5-10 INCH PRECIPITATION SURPLUSES DURING THE PAST 30 DAYS. THESE HEAVY
PRECIPITATION RISK AREAS ARE NOT QUITE AS PRONOUNCED ON TODAY’S PET
PRECIPITATION GUIDANCE, BUT ARE CONSISTENT WITH UNCALIBRATED ECMWF ENSEMBLE
MEAN GUIDANCE. ON THE WESTERN AND NORTHERN FLANKS OF THIS STORM SYSTEM, THERE
IS A SLIGHT RISK OF HEAVY SNOW POSTED, JAN 13-15. THIS AREA EXTENDS FROM THE
SOUTH-CENTRAL PLAINS NORTHEASTWARD ACROSS MOST OF THE MISSISSIPPI VALLEY AND
GREAT LAKES REGION, NORTHERN OHIO VALLEY, AND INTERIOR NORTHEAST. NEARER TO THE
SURFACE LOW’S TRACK, A MODERATE RISK FOR HEAVY SNOW IS INDICATED FOR THE SAME
TIME PERIOD FROM EASTERN KANSAS NORTHEASTWARD ACROSS THE UPPER GREAT LAKES
REGION. THIS SCENARIO IS CONSISTENT WITH 06Z AND 12Z DETERMINISTIC GFS
SOLUTIONS.
THE HIGH WIND RISK THAT HAD BEEN IN PLACE ACROSS SOUTHWESTERN MAINLAND ALASKA,
THE ALASKA PENINSULA, AND THE ALEUTIANS FOR THE PAST FEW DAYS HAS BEEN DROPPED
TODAY. THIS IS SUPPORTED BY THE PET WIND TOOL, AND IS CONSISTENT WITH A
PREDICTED STRONG MID-LEVEL RIDGE CENTERED OVER WESTERN ALASKA, ACCOMPANIED BY
WELL ABOVE-NORMAL 500-HPA HEIGHTS AND THE LACK OF SIGNIFICANT CYCLONIC ACTIVITY
IN THE REGION. ACCORDINGLY, NO WEEK-2 HAZARDS ARE INDICATED FOR ALASKA TODAY.
WHAT BEARS WATCHING IS THE DEVELOPMENT OF STRONG SURFACE HIGH PRESSURE OVER THE
YUKON OF NORTHWESTERN CANADA, WHICH MAY INDUCE GAP WINDS OVER THE SOUTHEAST
LATER IN THE PERIOD. FOR HAWAII, THE ACTIVE KONA LOW PATTERN PREDICTED IN
WEEK-1 LOOKS TO TIME OFF PRIOR TO WEEK-2, AND NO CORRESPONDING HAZARDS ARE
ISSUED.
FORECASTER: ANTHONY ARTUSA
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