Threats Assessment Discussion

336 
FXUS21 KWNC 011916
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST MARCH 01 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 4, SURFACE LOW 
PRESSURE IS EXPECTED TO BE OVER SOUTHEASTERN CANADA AS COLD HIGH PRESSURE 
BUILDS OVER THE EASTERN PART OF THE NATION. ONSHORE FLOW AROUND THE REAR SIDE 
OF THIS AREA OF HIGH PRESSURE IS ANTICIPATED OVER PARTS OF THE SOUTHERN PLAINS 
AND LOWER MISSISSIPPI VALLEY. A COLD FRONT ASSOCIATED WITH ONE OF THE AREAS OF 
LOW PRESSURE OVER THE NORTHERN U.S. IS ANTICIPATED TO MOVE ACROSS THE CENTRAL 
AND EASTERN U.S. MAR 4-8. COLD SURFACE HIGH PRESSURE IS FORECAST TO DOMINATE 
MUCH OF ALASKA AND THE ALEUTIANS DURING MOST OF THE ASSESSMENT PERIOD.
HAZARDS
HIGH WINDS FOR PARTS OF COASTAL SECTIONS OF THE NORTHEAST AND MID-ATLANTIC, 
SAT, MAR 4.
PERIODS OF HEAVY PRECIPITATION FOR PARTS OF NORTHERN CALIFORNIA, SAT-TUE, MAR 
4-7.
HEAVY PRECIPITATION FOR PARTS OF THE PACIFIC NORTHWEST, MON-TUE, MAR 6-7.
HEAVY SNOW FOR PARTS OF THE BITTERROOTS AND NORTHERN ROCKIES, SAT-SUN, MAR 4-5.
HEAVY RAIN FOR THE WESTERN GULF COAST, SAT-SUN, MAR 4-5.
CRITICAL FIRE WEATHER FOR PARTS OF THE SOUTHERN ROCKIES AND SOUTHERN PLAINS, 
SUN, MAR 5.
MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF NORTHERN NEW ENGLAND, SAT-SUN MAR 
4-5.
PERIODS OF MUCH BELOW NORMAL TEMPERATURES FOR MUCH OF MAINLAND ALASKA AND THE 
ALASKA PANHANDLE, SAT-WED, MAR 4-8.
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 EASTERN ALEUTIANS, THU-WED, MAR 9-MAR 15.
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR MOST OF CENTRAL AND 
SOUTHERN MAINLAND ALASKA, THU-WED, MAR 9-MAR 15.
HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF SOUTHERN AND EASTERN 
MAINLAND ALASKA, THU-MON, MAR 9-13.
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 SATURDAY MARCH 04 - WEDNESDAY MARCH 08: 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 4-8. PERIODS OF HEAVY PRECIPITATION (RAINFALL IN EXCESS OF 1 INCH IN 
24 HOURS AT LOWER ELEVATIONS, SNOWFALL IN EXCESS OF 6 INCHES AT HIGHER 
ELEVATIONS) ARE EXPECTED FOR PARTS OF NORTHERN CALIFORNIA MAR 4-7. HEAVY 
PRECIPITATION (RAINFALL IN EXCESS OF 2 INCHES IN 24 HOURS AT LOWER ELEVATIONS 
AND SNOWFALL IN EXCESS OF 8 INCHES IN 24 HOURS AT HIGHER ELEVATIONS) IS 
ANTICIPATED FOR PARTS OF THE PACIFIC NORTHWEST MAR 6-7, WHILE HEAVY SNOWFALL 
(AMOUNTS IN EXCESS OF 6 INCHES IN 24 HOURS) IS EXPECTED FOR PARTS OF THE 
BITTERROOTS AND NORTHERN ROCKIES MAR 4-5.
AN AREA OF LOW PRESSURE FORECAST TO DEEPEN OVER SOUTHEASTERN CANADA MAR 4-5 
LEADS TO HIGH WINDS (IN EXCESS OF 30 KNOTS) FOR PARTS OF COASTAL SECTIONS OF 
THE MID-ATLANTIC AND NORTHEAST MAR 4. BEHIND THIS AREA OF LOW PRESSURE, COLD 
HIGH PRESSURE IS FORECAST TO BUILD OVER THE EASTERN CONUS. MUCH BELOW NORMAL 
TEMPERATURES (NEGATIVE ANOMALIES EXCEEDING 10 DEGREES F) ARE ANTICIPATED FOR 
PARTS OF NORTHERN NEW ENGLAND MAR 4-5.
ONSHORE FLOW AROUND THE REAR SIDE OF HIGH PRESSURE FORECAST OVER THE EASTERN 
CONUS LEADS TO HEAVY RAINFALL (IN EXCESS OF 1 INCH IN 24 HOURS) FOR THE WESTERN 
GULF COAST MAR 4-5.
COLD HIGH PRESSURE OVER ALASKA IS FORECAST TO LEAD TO PERIODS OF MUCH BELOW 
NORMAL TEMPERATURES (NEGATIVE ANOMALIES IN EXCESS OF 20 DEGREES F) FOR MUCH OF 
MAINLAND ALASKA AND THE ALASKA PANHANDLE MAR 4-8.
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 AND HIGH WINDS 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 STILL 
PRECLUDES THE SPECIFICATION OF HAZARD SHAPES AT THE CURRENT TIME.
DRY FUELS AND GUSTY WINDS CREATE CRITICAL FIRE WEATHER CONDITIONS FOR PARTS OF 
THE SOUTHERN PLAINS AND SOUTHERN ROCKIES MAR 5. MARGINAL CRITICAL FIRE WEATHER 
CONDITIONS ARE ALSO EXPECTED OVER PARTS OF THE SOUTHERN AND CENTRAL PLAINS AND 
SOUTHERN ROCKIES MAR 4 AND MAR 6.
FOR THURSDAY MARCH 09 - WEDNESDAY MARCH 15: RIDGING IS FORECAST WEST OF ALASKA 
WITH TROUGHING EXPECTED OVER EASTERN MAINLAND ALASKA. THIS FLOW PATTERN FAVORS 
MUCH BELOW NORMAL TEMPERATURES FOR MUCH OF ALASKA. A SLIGHT RISK OF MUCH BELOW 
NORMAL TEMPERATURES IS INDICATED FOR MUCH OF THE ALASKA PANHANDLE, MAINLAND 
ALASKA, AND THE EASTERN ALEUTIANS MAR 9-15, A MODERATE RISK OF MUCH BELOW 
NORMAL TEMPERATURES FOR MUCH OF CENTRAL AND SOUTHERN MAINLAND ALASKA MAR 9-15, 
AND A HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF SOUTHERN AND 
EASTERN MAINLAND ALASKA MAR 9-13.
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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