903  
FXUS21 KWNC 272146  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST FEBRUARY 27 2018  
 
SYNOPSIS: EARLY IN THE PERIOD, A LOW-PRESSURE SYSTEM IS FORECAST TO INTENSIFY  
NEAR THE NORTHEAST. SIMULTANEOUSLY, A LOW-PRESSURE SYSTEM IS ALSO FORECAST TO  
MOVE ACROSS THE WESTERN CONUS, THEN THE GREAT LAKES, BEFORE INTENSIFYING NEAR  
THE GREAT LAKES. THE COLD FRONT ASSOCIATED WITH THIS LOW-PRESSURE SYSTEM IS  
FORECAST TO MOVE ACROSS THE SOUTHERN PLAINS AND SOUTHEAST DURING THE WEEKEND  
AND INTO THE FIRST HALF OF NEXT WEEK. AN UNSETTLED PATTERN IS LIKELY OVER  
SOUTHERN AND WESTERN ALASKA LATER IN WEEK-1 AND POTENTIALLY INTO WEEK-2.  
 
HAZARDS  
 
ENHANCED WILDFIRE RISK ACROSS PORTIONS OF THE THE SOUTHERN HIGH PLAINS,  
FRI-SAT, MAR 2-MAR 3.  
 
HEAVY RAIN ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY, MON-TUE, MAR 5-MAR  
6.  
 
HEAVY SNOW ACROSS PORTIONS OF THE SIERRA NEVADAS, FRI, MAR 2.  
 
HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL GREAT BASIN, FRI-SAT, MAR 2-MAR 3.  
 
FLOODING POSSIBLE ACROSS PORTIONS OF THE SOUTHERN APPALACHIANS, THE OHIO  
VALLEY, AND THE TENNESSEE VALLEY.  
 
FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY,  
THE TENNESSEE VALLEY, THE GREAT LAKES, THE MIDDLE MISSISSIPPI VALLEY, THE UPPER  
MISSISSIPPI VALLEY, THE SOUTHERN PLAINS, AND THE OHIO VALLEY.  
 
FLOODING LIKELY ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY, THE SOUTHERN  
APPALACHIANS, THE OHIO VALLEY, AND THE TENNESSEE VALLEY.  
 
HIGH WINDS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN ROCKIES, THE SOUTHERN  
ROCKIES, THE CENTRAL GREAT BASIN, AND THE SOUTHWEST, FRI-SAT, MAR 2-MAR 3.  
 
HIGH WINDS FROM THE CAROLINAS TO NEW ENGLAND, FRI-SAT, MAR 2-MAR 3.  
 
MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF CALIFORNIA, THE NORTHERN AND  
CENTRAL GREAT BASIN, THE PACIFIC NORTHWEST, AND THE SOUTHWEST, SAT-TUE, MAR  
3-MAR 6.  
 
MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE  
NORTHERN ROCKIES, SUN-TUE, MAR 4-MAR 6.  
 
MUCH ABOVE NORMAL TEMPERATURES ACROSS PORTIONS OF NORTHERN MAINLAND ALASKA,  
FRI-MON, MAR 2-MAR 5.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FROM THE PACIFIC NORTHWEST TO THE  
CENTRAL AND NORTHERN GREAT PLAINS, WED-THU, MAR 7-MAR 8.  
 
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE NORTHERN  
PLAINS AND THE NORTHERN ROCKIES, WED-THU, MAR 7-MAR 8.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE SOUTHEAST,  
THE SOUTHERN APPALACHIANS, THE LOWER MISSISSIPPI VALLEY, THE SOUTHERN PLAINS,  
AND THE TENNESSEE VALLEY, THU-FRI, MAR 8-MAR 9.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF MAINLAND ALASKA,  
FRI-SUN, MAR 9-MAR 11.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE CENTRAL GREAT BASIN AND  
CALIFORNIA, THU-SAT, MAR 8-MAR 10.  
 
SEVERE DROUGHT ACROSS THE CENTRAL PLAINS, THE CENTRAL ROCKIES, THE LOWER  
MISSISSIPPI VALLEY, THE CENTRAL GREAT BASIN, THE NORTHERN PLAINS, THE SOUTHERN  
ROCKIES, THE MIDDLE MISSISSIPPI VALLEY, CALIFORNIA, THE SOUTHERN PLAINS, AND  
THE SOUTHWEST.  
 
DETAILED SUMMARY  
 
FOR FRIDAY MARCH 02 - TUESDAY MARCH 06: A SURFACE LOW IS FORECAST NEAR THE  
NORTHEAST ON FRIDAY, AND POTENTIALLY MOVING AWAY FROM THE EAST COAST. HIGH  
WINDS (IN EXCESS OF 40MPH) WRAPPING AROUND THE SYSTEM ARE LIKELY OVER THE  
NORTHEAST AND MID-ATLANTIC, WITH WINDS IN PLACES WITH HIGHER TERRAIN LIKELY  
EXCEEDING 50MPH WIND. SOME SNOWS ARE LIKELY AS WELL, THOUGH THOSE SHOULD BE  
TAPERING OFF DURING THE AFTERNOON OF FRIDAY.  
 
A STORM SYSTEM IS FORECAST TO MOVE ACROSS THE WESTERN CONUS, DURING THE  
UPCOMING WEEKEND. HEAVY SNOWS ARE LIKELY IN THE SIERRAS, WITH AMOUNTS LIKELY TO  
EXCEED 8 INCHES OVER LARGE AREAS AND SOME LOCATIONS FORECAST TO MEASURE  
SNOWFALL TOTALS IN FEET RATHER THAN INCHES. AS THE SYSTEM MOVES EAST, HEAVY  
SNOWS ARE PREDICTED TO SPREAD TO NEVADA, FOLLOWED BY UTAH, THOUGH SNOWFALL  
TOTALS ARE ANTICIPATED TO BE LOWER. BEHIND THIS LOW-PRESSURE SYSTEM, COLDER AIR  
IS FORECAST OVER THE WEST. DAILY MINIMUM TEMPERATURES BETWEEN 12 AND 20 DEGREES  
F BELOW AVERAGE ARE PREDICTED FROM NORTHERN CALIFORNIA DURING MARCH 3-6, AND  
ALSO OVER MONTANA DURING MARCH 4-6. AHEAD OF THE SYSTEM, CRITICAL FIRE WEATHER  
CONDITIONS ARE LIKELY OVER THE SOUTHERN HIGH PLAINS, MARCH 2-3. HIGH WINDS ARE  
ALSO LIKELY WITH THIS LOW-PRESSURE SYSTEM IN THE FOUR CORNERS REGION, WITH  
GLOBAL MODELS SHOWING WIND SPEEDS OF 40 MPH, WHICH IMPLIES LIKELY HIGHER SPEEDS  
WHERE TERRAIN FUNNELING INCREASES LOCAL WINDS.  
 
AS THE AFOREMENTIONED LOW-PRESSURE SYSTEM MOVES ACROSS THE COUNTRY, THE COLD  
FRONT IS FORECAST TO SETTLE ACROSS THE SOUTHERN GREAT PLAINS. THIS FRONT SHOULD  
SERVE AS A FOCUSING MECHANISM FOR HEAVY PRECIPITATION (2 INCHES) ACROSS AREAS  
ALREADY SATURATED. ADDITIONALLY, THERE IS A MARGINAL THREAT FOR SEVERE WEATHER  
FROM TEXAS TO THE SOUTHEAST, AS THE FRONT MOVES THAT WAY DURING SUNDAY AND  
MONDAY.  
 
A STORM SYSTEM IN THE BERING SEA MAY SUPPORT PERSISTENT, STRONG SOUTHWESTERLY  
FLOW FROM THE MIDDLE TO END OF THE DAY 3 TO 7 PERIOD. THIS PATTERN FAVORS HIGH  
SIGNIFICANT WAVE HEIGHTS ACROSS COASTAL PARTS OF THE ALEUTIANS, MAR 3 TO 4,  
THOUGH TODAY'S MODEL RUNS SHOW HEIGHTS SLIGHTLY LOWER THAN YESTERDAY, SO NO  
HAZARD IS DEPICTED. STRONG SOUTHERLY FLOW IS ANTICIPATED FOR PARTS OF MAINLAND  
ALASKA DURING MARCH 3-5. THIS FLOW PATTERN, IN COMBINATION WITH BELOW NORMAL  
ICE COVER IN THE BERING SEA ALONG THE WEST COAST OF MAINLAND ALASKA, FAVORS  
MUCH ABOVE NORMAL TEMPERATURES ACROSS THE NORTH SLOPE. SOME AREAS IN THIS  
REGION MAY EXPERIENCE TEMPERATURES 40 DEG F ABOVE NORMAL.  
 
FOR WEDNESDAY MARCH 07 - TUESDAY MARCH 13: MID-LEVEL TROUGHING IS FORECAST FOR  
THE NORTHWESTERN QUARTER OF THE CONUS FROM THE BEGINNING TO MIDDLE OF WEEK-2,  
SUPPORTING A SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES IN THIS AREA MAR 7  
TO 8. MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES IS IDENTIFIED FOR  
PORTIONS OF THE NORTHERN PLAINS AND THE NORTHERN ROCKIES, MAR 7 TO 8. MID-LEVEL  
TROUGHING IS ANTICIPATED ACROSS MOST OF MAINLAND ALASKA, SUPPORTING A SLIGHT  
RISK OF MUCH BELOW NORMAL TEMPERATURES ACROSS PARTS OF MAINLAND ALASKA, MAR 9  
TO 11. THE GEFS REFORECAST TOOL INDICATES A 20% CHANCE OR GREATER OF THE  
MINIMUM TEMPERATURE IN THE AFOREMENTIONED REGIONS REACHING THE LOWEST 15TH  
PERCENTILE COMPARED TO NORMAL, WITH AT LEAST A 40% CHANCE IN THE NORTHERN  
ROCKIES.  
 
ACROSS THE SOUTHEAST, THERE IS A RISK OF A LATE SEASON FROST ACROSS THE  
INTERIOR SOUTHEAST. MODEL OUTPUTS INDICATE A 40-60% CHANCE FOR TEMPERATURES TO  
FALL BELOW 40 DEG F, AND SLIGHTLY ELEVATED CHANCES FOR TEMPERATURES TO DROP  
BELOW THE FREEZING MARK, IN THE AREA DEPICTED ON THE MAP. THIS AREA IS  
CONSISTENT WITH COLD AIR MOVING SOUTHWARD BEHIND THE LOW-PRESSURE SYSTEM  
FORECAST OVER THE GREAT LAKES BY DAY 7.  
 
IN GENERAL, THE MEAN PATTERN FOR WEEK-2 FAVORS MID-LEVEL TROUGHING ACROSS THE  
NORTHEASTERN PACIFIC OCEAN INTO PARTS OF WESTERN CONUS. THIS PATTERN SUPPORTS  
STRONG ONSHORE FLOW TO PARTS OF THE WESTERN CONUS. THIS PATTERN SUPPORT A  
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE CENTRAL GREAT BASIN, AND  
CALIFORNIA, MAR 8 TO 10. HOWEVER, THERE IS SIGNIFICANT DISAGREEMENT BETWEEN THE  
GEFS AND ECWMF, WITH THE ECMWF DEPICTING A WETTER SOLUTION. THE HEAVY  
PRECIPITATION AREA HIGHLIGHTED DENOTES WHERE THE GEFS AND ECMWF REFORECAST TOOL  
SHOW SOME AGREEMENT REGARDING ENHANCED CHANCES FOR HEAVY PRECIPITATION BOTH  
SPATIALLY AND TEMPORALLY.  
 
THE U.S. DROUGHT MONITOR, VALID ON FEB 20, 2018 INDICATES A SLIGHT DECREASE IN  
THE COVERAGE OF SEVERE TO EXCEPTIONAL DROUGHT (D2-D4) FROM 18.04% LAST WEEK TO  
17.76% THIS WEEK. A FEW OF THE MORE SUBSTANTIAL REVISIONS MADE TO THE MAP THIS  
WEEK INCLUDE AN INCREASE IN THE D1 COVERAGE OVER OREGON, A DECREASE IN THE D3  
COVERAGE OVER NORTHERN TEXAS, AND THE ADDITION OF D3 COVERAGE OVER THE FOUR  
CORNERS REGION.  
 
FORECASTER: MATTHEW ROSENCRANS  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page