Prognostic Meteorological Discussion
Issued by NWS

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FXUS21 KWNC 281934
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 28 2017

SYNOPSIS: EARLY IN THE PERIOD, A SERIES OF SURFACE LOW-PRESSURE SYSTEMS ARE
FORECAST TO MOVE ACROSS THE NORTHERN TIER OF THE U.S. ON MAR 3, SURFACE LOW
PRESSURE IS EXPECTED TO BE OVER SOUTHEASTERN CANADA AS COLD HIGH PRESSURE
BUILDS OVER THE NORTH-CENTRAL AND THEN NORTHEASTERN PARTS OF THE NATION.
SURFACE LOW PRESSURE IS FORECAST TO PASS NORTH OF NORTHEAST MAINLAND ALASKA MAR
3 AS ITS TRAILING COLD FRONT MOVES OVER THE REGION MAR 4-5. COLD SURFACE HIGH
PRESSURE IS FORECAST TO DOMINATE MUCH OF THE REST OF MAINLAND ALASKA AND THE
ALEUTIANS INTO THE WEEK-2 PERIOD.

HAZARDS

MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF THE NORTHERN PLAINS AND UPPER
MISSISSIPPI VALLEY, FRI, MAR 3.

MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF NORTHERN NEW YORK AND NEW ENGLAND,
SAT MAR 4.

HEAVY PRECIPITATION FOR PARTS OF NORTHERN CALIFORNIA, SAT-MON, MAR 4-7.

PERIODS OF HEAVY SNOW FOR PARTS OF THE OLYMPICS AND CASCADES, FRI-MON, MAR 3-6.

HEAVY SNOW FOR PARTS OF THE BITTERROOTS AND NORTHERN ROCKIES, SAT-SUN, MAR 4-5.

HIGH WINDS FOR PARTS OF COASTAL SECTIONS OF NEW ENGLAND, SAT, MAR 4.

PERIODS OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF CENTRAL AND SOUTHERN
MAINLAND ALASKA AND THE ALASKA PANHANDLE, FRI-TUE, MAR 3-7.

HIGH WINDS FOR PARTS OF NORTHEAST MAINLAND ALASKA, FRI, MAR 3.

FLOODING POSSIBLE FOR PORTIONS OF THE UPPER AND MIDDLE MISSISSIPPI VALLEY.

SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR MOST OF THE ALASKA PANHANDLE,
MAINLAND ALASKA, AND THE ALEUTIANS, WED-TUE, MAR 8-MAR 14.

MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR MOST OF CENTRAL AND EASTERN
MAINLAND ALASKA AND THE ALASKA PENINSULA, WED-MON, MAR 8-MAR 13.

HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF SOUTHERN AND CENTRAL
MAINLAND ALASKA AND THE ALASKA PENINSULA, WED-FRI, MAR 8-10.

SEVERE DROUGHT ACROSS THE CENTRAL PLAINS, THE LOWER MISSISSIPPI VALLEY, THE
TENNESSEE VALLEY, THE MID-ATLANTIC, CALIFORNIA, THE SOUTHEAST, THE SOUTHERN
APPALACHIANS, THE SOUTHERN PLAINS, AND THE SOUTHWEST.

DETAILED SUMMARY

FOR FRIDAY MARCH 03 - TUESDAY MARCH 07: A SERIES OF LOW PRESSURE SYSTEMS AT THE
SURFACE AND ALOFT ARE EXPECTED TO DOMINATE MUCH OF THE NORTHERN TIER OF THE
U.S. MAR 3-7. PERIODS OF HEAVY SNOW (IN EXCESS OF 6 INCHES IN 24 HOURS) ARE
EXPECTED FOR PARTS OF THE OLYMPICS AND CASCADES (MAR 3-6) AND FOR PARTS OF THE
BITTERROOTS AND NORTHERN ROCKIES (MAR 4-5). HEAVY PRECIPITATION (RAINFALL
EXCEEDING 1 INCH IN 24 HOURS AT LOWER ELEVATIONS, SNOWFALL EXCEEDING 8 INCHES
IN 24 HOURS AT HIGHER ELEVATIONS) IS ANTICIPATED FOR PARTS OF NORTHERN
CALIFORNIA  MAR 4-7.



AN AREA OF LOW PRESSURE FORECAST TO DEEPEN OVER SOUTHEASTERN CANADA MAR 3-4
LEADS TO HIGH WINDS (IN EXCESS OF 30 KNOTS) FOR PARTS OF COASTAL SECTIONS OF
NEW ENGLAND MAR 4. BEHIND THIS AREA OF LOW PRESSURE, COLD HIGH PRESSURE IS
FORECAST TO BUILD OVER THE NORTH-CENTRAL THEN NORTHEASTERN CONUS. MUCH BELOW
NORMAL TEMPERATURES (NEGATIVE ANOMALIES EXCEEDING 10 DEGREES F) ARE ANTICIPATED
FOR PARTS OF THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY MAR 3, AND PARTS
OF NORTHERN NEW YORK AND NEW ENGLAND MAR 4.



LOW PRESSURE PASSING NORTH OF MAINLAND ALASKA IS EXPECTED TO LEAD TO HIGH WINDS
(SPEEDS IN EXCESS OF 35 KNOTS) FOR PARTS OF NORTHEAST MAINLAND ALASKA MAR 3.
THE COMBINATION OF HIGH WINDS, AND FALLING OR BLOWING SNOW IS ANTICIPATED TO
CAUSE BLIZZARD-LIKE CONDITIONS FOR PART OF THE REGION. COLD HIGH PRESSURE IS
FORECAST TO LEAD TO PERIODS OF MUCH BELOW NORMAL TEMPERATURES (NEGATIVE
ANOMALIES IN EXCESS OF 20 DEGREES F) FOR PARTS OF CENTRAL AND SOUTHERN MAINLAND
ALASKA AND THE ALASKA PANHANDLE MAR 3-7.



ONSHORE FLOW IS FORECAST TO LEAD TO PRECIPITATION NEAR THE SOUTHEAST TEXAS
COAST MAR 3-4 BUT THE HEAVIEST RAINFALL IS CURRENTLY EXPECTED TO REMAIN
OFFSHORE SO NO HAZARDS ARE ANTICIPATED.



LOW PRESSURE NEAR THE NORTHERN PLAINS MAR 6 IS EXPECTED TO MOVE INTO EASTERN
CANADA MAR 7 AS ITS TRAILING FRONTAL SYSTEM MOVES ACROSS THE EASTERN CONUS.
THIS MAY LEAD TO WINTRY PRECIPITATION FOR PARTS OF THE NORTHERN PLAINS, UPPER
MISSISSIPPI VALLEY, AND NEW ENGLAND, AND SHOWERS AND THUNDERSTORMS WITH THE
FRONTAL PASSAGE, BUT VERY LARGE MODEL SPREAD PRECLUDES THE SPECIFICATION OF
HAZARD SHAPES AT THE CURRENT TIME.



DRY FUELS AND GUSTY WINDS MAY CREATE MARGINAL CRITICAL FIRE WEATHER CONDITIONS
FOR PARTS OF THE SOUTHERN PLAINS SEVERAL DAYS DURING THE PERIOD BUT MODEL
UNCERTAINTY PRECLUDES THE SPECIFICATION OF A HAZARD SHAPE AT THE CURRENT TIME.

FOR WEDNESDAY MARCH 08 - TUESDAY MARCH 14: RIDING IS FORECAST WEST OF ALASKA
WITH TROUGHING EXPECTED OVER EASTERN MAINLAND ALASKA. THIS FLOW PATTERN FAVORS
MUCH BELOW NORMAL TEMPERATURES FOR MUCH OF ALASKA. THE GEFS REFORECAST
PROBABILISTIC TEMPERATURE TOOL INDICATES A SLIGHT RISK OF MUCH BELOW NORMAL
TEMPERATURES FOR MUCH OF THE ALASKA PANHANDLE, MAINLAND ALASKA, AND THE
ALEUTIANS MAR 8-14, A MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR MUCH
OF CENTRAL AND EASTERN MAINLAND ALASKA AND THE ALASKA PENINSULA MAR 8-13, AND A
HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF SOUTHERN AND CENTRAL
MAINLAND ALASKA AND THE ALASKA PENINSULA MAR 8-10.



ACCORDING TO THE U.S. DROUGHT MONITOR VALID ON FEBRUARY 21, SEVERE DROUGHT IS
DESIGNATED ACROSS PARTS OF CALIFORNIA, ARIZONA, THE GREAT PLAINS, ARKANSAS,
SOUTH TEXAS, AND THE EASTERN U.S. COVERAGE OF SEVERE, OR GREATER INTENSITY,
DROUGHT THROUGHOUT THE CONTINENTAL U.S. REMAINED NEARLY STEADY AT 3.31 PERCENT.
CALIFORNIA, TO THE NORTH OF POINT CONCEPTION, IS FREE OF LONG-TERM SEVERE
DROUGHT.

FORECASTER: RANDY SCHECHTER

$$



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