Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
695
FXUS21 KWNC 091927
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 09 2016

SYNOPSIS: A STRONG AREA OF UPPER-LEVEL LOW PRESSURE IS EXPECTED TO REMAIN OVER
THE EASTERN U.S. THROUGH THE WEEKEND WITH ARCTIC SURFACE HIGH PRESSURE SHIFTING
SOUTH FROM CANADA. A LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP ACROSS THE
EAST-CENTRAL U.S. BY MONDAY. THE AREA OF UPPER-LEVEL HIGH PRESSURE ACROSS THE
WESTERN U.S. IS EXPECTED TO WEAKEN EARLY IN THE PERIOD BEFORE POTENTIALLY
REBUILDING LATER IN WEEK-2. AN AREA OF UPPER-LEVEL LOW PRESSURE IS FORECAST TO
PERSIST ACROSS THE ALEUTIANS DURING THE NEXT TWO WEEKS.

HAZARDS

MUCH BELOW-NORMAL TEMPERATURES FOR THE UPPER MISSISSIPPI VALLEY, GREAT LAKES,
AND MIDWEST, FRI-SAT, FEB 12-13.

MUCH BELOW-NORMAL TEMPERATURES FOR THE EASTERN U.S., FRI-MON, FEB 12-15.

HEAVY PRECIPITATION FOR NORTHERN IDAHO AND PARTS OF WASHINGTON, SUN-MON, FEB
14-15.

FLOODING OCCURRING OR LIKELY ACROSS PARTS OF THE SOUTHEAST AND LOWER
MISSISSIPPI VALLEY.

SEVERE DROUGHT ACROSS PARTS OF THE WESTERN U.S. AND PUERTO RICO.

DETAILED SUMMARY

FOR FRIDAY FEBRUARY 12 - TUESDAY FEBRUARY 16: A HIGHLY AMPLIFIED UPPER-LEVEL
TROUGH ACROSS EASTERN NORTH AMERICA IS LIKELY TO RESULT IN A 1044-HPA SURFACE
HIGH SHIFTING SOUTH FROM CANADA INTO THE EASTERN U.S. THIS WEEKEND.
DETERMINISTIC 6Z GFS AND 0Z ECMWF MODEL RUNS REMAIN CONSISTENT THAT 850-HPA
TEMPERATURES BELOW -24 DEGREES C SHIFT EAST FROM THE GREAT LAKES ON FRIDAY TO
THE NORTHEAST THIS WEEKEND. THE MOST EXTREME ANOMALOUS COLD ACROSS THE UPPER
MISSISSIPPI VALLEY, GREAT LAKES, AND MIDWEST IS FORECAST ON SATURDAY MORNING
WHEN MINIMUM TEMPERATURES OF 0 TO -20 DEGREES F CAN BE EXPECTED. ON SUNDAY
MORNING, SUBZERO MINIMUM TEMPERATURES ARE FORECAST ACROSS THE NORTHEAST WITH
SINGLE DIGITS ABOVE ZERO MINIMUM TEMPERATURES ACROSS THE MID-ATLANTIC. THESE
MINIMUM TEMPERATURES ARE 20 TO 25 DEGREES F BELOW-NORMAL FOR MID-FEBRUARY.
ALTHOUGH WIND SPEEDS ARE LIKELY TO REMAIN BELOW HAZARDS CRITERIA, GUSTY WINDS
OF 15 TO 25 MPH THIS WEEKEND ARE LIKELY TO CREATE DANGEROUS WIND CHILL VALUES
ACROSS THE NORTHEAST. FREEZING TEMPERATURES ARE LIKELY TO EXTEND AS FAR SOUTH
AS THE FLORIDA PANHANDLE ON SUNDAY MORNING.



ON FRIDAY AND SATURDAY, STRONG COLD AIR ADVECTION IS FORECAST TO PROMOTE
LAKE-EFFECT SNOW DOWNWIND OF THE GREAT LAKES. THE VERY DRY AIRMASS IS EXPECTED
TO LIMIT LAKE-EFFECT SNOW AMOUNTS. UPSLOPE FLOW AND STRONG COLD AIR ADVECTION
IS ALSO FORECAST TO BRING LIGHT TO MODERATE SNOW, GENERALLY LESS THAN 4 INCHES,
TO THE CENTRAL APPALACHIANS ON FRIDAY. MODEL GUIDANCE IS IN BETTER AGREEMENT
TODAY THAT SURFACE LOW DEVELOPMENT ASSOCIATED WITH THE AMPLIFYING UPPER-LEVEL
TROUGH OCCURS OFFSHORE WITH ONLY LIGHT SNOW ACROSS NEW ENGLAND.



A SHORTWAVE TROUGH AND WARM AIR ADVECTION ARE EXPECTED TO RESULT IN SNOW AND/OR
FREEZING RAIN ACROSS THE MIDDLE MISSISSIPPI VALLEY, OHIO VALLEY, AND TENNESSEE
VALLEY ON SUNDAY. THIS WINTER WEATHER IS EXPECTED TO SPREAD EAST INTO THE
CENTRAL APPALACHIANS AND MID-ATLANTIC EARLY NEXT WEEK. FORECAST CONFIDENCE
REGARDING PRECIPITATION TYPE AND AMOUNTS ACROSS THESE AREAS IS LOW DUE TO
VARYING MODEL SOLUTIONS ON THE EVOLVING PATTERN.



THE UPPER-LEVEL RIDGE OVER WESTERN NORTH AMERICA IS FORECAST TO WEAKEN AND
ALLOW THE RETURN OF ONSHORE FLOW TO THE PACIFIC NORTHWEST LATER IN THE WEEK.
DUE TO ENHANCED PACIFIC MOISTURE WITH THIS ONSHORE FLOW ALONG WITH AN INCREASE
IN PRECIPITATION AMOUNTS FORECAST AMONG THE MODEL SOLUTIONS, A HEAVY
PRECIPITATION HAZARD IS POSTED FOR COASTAL WASHINGTON AND THE NORTHERN
CASCADES. 48-HOUR PRECIPITATION AMOUNTS FROM FEBRUARY 14-15 ARE EXPECTED TO
LOCALLY EXCEED 3 INCHES, LIQUID EQUIVALENT, FOR THIS REGION. SNOW LEVELS ARE
LIKELY TO BE RELATIVELY HIGH ACROSS THE NORTHERN CASCADES. HEAVY RAIN AND
HIGH-ELEVATION SNOW (1 INCH OR MORE PER 24 HOURS) IS ALSO EXPECTED ACROSS
NORTHERN IDAHO FROM FEBRUARY 14-15.



HEAVY RAINFALL DURING THE PAST FEW WEEKS TRIGGERED MINOR TO MODERATE FLOODING
ALONG THE FOLLOWING RIVERS: ALTAMAHA AND SAVANNAH RIVERS IN GEORGIA, CAPE FEAR
RIVER IN NORTH CAROLINA, EDISTO RIVER IN SOUTH CAROLINA, CHOCTAWHATCHEE RIVER
IN THE FLORIDA PANHANDLE, AND PEARL RIVER IN MISSISSIPPI.



A PERSISTENT AREA OF LOW PRESSURE AND ONSHORE FLOW ARE EXPECTED TO BRING
PERIODS OF INCREASED WINDS AND PRECIPITATION TO COASTAL SOUTHERN ALASKA AND THE
ALASKA PANHANDLE DURING THIS PERIOD. HOWEVER, HAZARDOUS PRECIPITATION AMOUNTS
AND WIND SPEEDS ARE NOT FORECAST ACROSS THESE AREAS.

FOR WEDNESDAY FEBRUARY 17 - TUESDAY FEBRUARY 23: THE 0Z/6Z GFS ENSEMBLE MEANS
FAVOR A FASTER RETURN OF THE WESTERN CONUS RIDGE WITH A TROUGH DOWNSTREAM NEAR
THE EAST COAST. LARGE SPREAD EXISTS AMONG THE 0Z CANADIAN AND 0Z ECMWF ENSEMBLE
MEMBERS ACROSS NORTH AMERICA. DUE TO THESE VARYING MODEL SOLUTIONS, NO SPECIFIC
HAZARDS EXCEPT FOR ONGOING SEVERE TO EXCEPTIONAL DROUGHT ARE POSTED.



ACCORDING TO THE U.S. DROUGHT MONITOR VALID ON FEBRUARY 2, THE COVERAGE OF
SEVERE TO EXCEPTIONAL (D2-D4) DROUGHT ACROSS THE 50 U.S. STATES AND PUERTO RICO
DECREASED SLIGHTLY FROM 7.13 PERCENT TO 7.06 PERCENT. SEVERE TO EXCEPTIONAL
DROUGHT IS LIMITED TO THE WESTERN THIRD OF THE CONTIGUOUS U.S. AND PUERTO RICO

FORECASTER: BRAD PUGH

$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.