036  
FXUS21 KWNC 072136  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST NOVEMBER 07 2017  
 
SYNOPSIS: A LOW-PRESSURE SYSTEM IS FORECAST TO DEEPEN NEAR THE NORTHEAST LATER  
THIS WEEK, WITH HIGH PRESSURE BUILDING IN BEHIND IT. THIS HIGH-PRESSURE SYSTEM  
IS FORECAST TO SLIDE FROM THE UPPER GREAT LAKES TO THE NORTHEAST DURING THE  
WEEKEND. MULTIPLE LOW-PRESSURE SYSTEMS ARE FORECAST TO IMPACT THE PACIFIC  
NORTHWEST, INCLUDING INTO THE EARLY PORTION OF WEEK-2. A STRONG LOW-PRESSURE  
SYSTEM IS FORECAST OVER NORTHWESTERN ALASKA, BEFORE MOVING SOUTHWARD AND  
MERGING WITH A PERSISTENT AREA OF LOW-PRESSURE NEAR WESTERN CANADA. A COLDER  
PATTERN IS LIKELY OVER EASTERN ALASKA DURING WEEK-2.  
 
HAZARDS  
 
HEAVY PRECIPITATION ACROSS PORTIONS OF CALIFORNIA, THE PACIFIC NORTHWEST, AND  
THE NORTHERN ROCKIES, SUN-TUE, NOV 12-NOV 14.  
 
HEAVY PRECIPITATION ACROSS PORTIONS OF THE PACIFIC NORTHWEST, SAT, NOV 11.  
 
HEAVY SNOW ACROSS PORTIONS OF THE NORTHERN ROCKIES AND THE NORTHERN GREAT  
BASIN, FRI, NOV 10 AND MON-TUE, NOV 13-NOV 14.  
 
HIGH WINDS ACROSS PORTIONS OF THE NORTHEAST AND THE GREAT LAKES, FRI, NOV 10.  
 
MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE NORTHEAST, THE CENTRAL  
APPALACHIANS, THE NORTHERN PLAINS, THE MIDDLE MISSISSIPPI VALLEY, THE  
MID-ATLANTIC, THE SOUTHERN APPALACHIANS, THE UPPER MISSISSIPPI VALLEY, THE  
GREAT LAKES, AND THE OHIO VALLEY, FRI-SUN, NOV 10-NOV 12.  
 
HEAVY SNOW ACROSS PORTIONS OF MAINLAND ALASKA, SUN, NOV 12.  
 
HIGH WINDS ACROSS PORTIONS OF MAINLAND ALASKA, SAT-SUN, NOV 11-NOV 12.  
 
MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE ALASKA PANHANDLE AND  
MAINLAND ALASKA, TUE, NOV 14.  
 
FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF FLORIDA.  
 
FLOODING LIKELY ACROSS PORTIONS OF WESTERN NEW YORK.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE GREAT LAKES,  
THE UPPER MISSISSIPPI VALLEY, AND THE NORTHERN PLAINS, FRI-SUN, NOV 17-NOV 19.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE ALASKA  
PANHANDLE AND MAINLAND ALASKA, WED-SUN, NOV 15-NOV 19.  
 
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE ALASKA  
PANHANDLE AND MAINLAND ALASKA, WED-THU, NOV 15-NOV 16.  
 
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF MAINLAND  
ALASKA, WED, NOV 15.  
 
HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE ALASKA  
PANHANDLE AND MAINLAND ALASKA, WED-THU, NOV 15-NOV 16.  
 
SEVERE DROUGHT ACROSS HAWAII, THE SOUTHERN PLAINS, THE NORTHERN PLAINS, THE  
NORTHERN ROCKIES, AND THE SOUTHWEST.  
 
DETAILED SUMMARY  
 
FOR FRIDAY NOVEMBER 10 - TUESDAY NOVEMBER 14: A LOW-PRESSURE SYSTEM IS FORECAST  
TO INTENSIFY OVER SOUTHEASTERN CANADA DURING THE WEEKEND, WITH THE ASSOCIATED  
COLD FRONT PUSHING SOUTHWARD TO THE GULF OF MEXICO. HIGH WINDS (GREATER THAN 35  
KNOTS OVER THE GREAT LAKES, IN EXCESS OF 40 MPH OVER LAND, AND HIGHER WIND  
SPEEDS OVER ELEVATED AND EXPOSED AREAS OF THE NORTHEAST) ARE LIKELY BEHIND THE  
FRONT. THOSE WINDS WILL SIGNAL THE ARRIVAL OF COLDER AIR, WITH TEMPERATURES  
12-24 DEG F BELOW NORMAL OVER MUCH OF THE NORTHERN TIER OF THE CONUS. THE COLD  
AIR AND NORTHWEST WINDS SHOULD SUPPORT LAKE ENHANCED SNOWFALL FRIDAY, NOV 10,  
THOUGH NO MAJOR ACCUMULATIONS ARE EXPECTED.  
 
SOME MODERATION IS LIKELY AS THE COLDER AIR SLIDES FURTHER EAST, BUT AREAS FROM  
THE CAROLINAS TO THE MID-ATLANTIC AND LONG ISLAND COULD SEE THEIR FIRST FREEZE  
OF THE YEAR. FREEZING TEMPERATURES ARE FORECAST FOR BOTH SATURDAY AND SUNDAY  
MORNING, FOR AREAS EAST OF THE APPALACHIANS.  
 
AN ACTIVE PERIOD IS FORECAST FOR THE NORTHWEST QUADRANT OF THE COUNTRY. AS THE  
MOISTURE MOVES INLAND, HEAVY SNOWS AND HIGHER WINDS (THOUGH THE WINDS ARE  
LIKELY TO BE CONTAINED TO HIGHER ELEVATIONS) ARE FORECAST OVER IDAHO AND IN THE  
VICINITY OF YELLOWSTONE NATIONAL PARK DURING FRIDAY. MODERATE TO LOCALLY HEAVY  
RAINS (1-2 INCHES WITH LOCALLY HIGHER AMOUNTS) WITH SNOW AT HIGHER ELEVATIONS  
ARE PREDICTED FOR THE PACIFIC NORTHWEST DURING SATURDAY. RIVERS ARE LIKELY TO  
RISE QUICKLY AS THIS SYSTEM SHOULD HAVE A GOOD FEED OF MOISTURE. MODEL  
FORECASTS SHOW ANOTHER SYSTEM MOVING INTO THE AREA ON SUNDAY, WITH LINGERING  
HEAVY PRECIPITATION IMPACTS INTO TUESDAY OF NEXT WEEK. HEAVY SNOWS ARE AGAIN  
LIKELY TO IMPACT THE BITTERROOTS AND SOUTHWARD TO YELLOWSTONE.  
 
A LOW-PRESSURE SYSTEM IS FORECAST TO DEEPEN OVER NORTHWESTERN ALASKA, BRINGING  
HIGH WINDS (IN EXCESS OF 35MPH) TO THE WESTERN COAST OF ALASKA. UNCERTAINTY  
ABOUT THE EXACT MAGNITUDE OF THE WIND SPEEDS IS ELEVATED AS THE ECMWF RUNS ARE  
LESS BULLISH. COASTAL FLOODING IS POSSIBLE, THOUGH THE UNCERTAINTY IN THE FETCH  
IS TOO HIGH, AT THIS TIME, TO DEPICT THAT HAZARD. HEAVY SNOW IS LIKELY TO  
OVERSPREAD CENTRAL ALASKA, WITH RATIOS LIKELY TOPPING 15 TO 1, AND AN NEARLY AN  
INCH OF LIQUID EQUIVALENT PREDICTED. TOWARD THE END OF THE PERIOD, COLD AIR IS  
LIKELY OVER SOUTHEAST ALASKA, WITH HIGH TEMPERATURES 12-16 DEG F BELOW NORMAL.  
 
FLOODING IS LIKELY TO RECEDE IN WESTERN NEW YORK, WHILE FLOODING IS FORECAST TO  
CONTINUE ALONG THE ST. JOHNS RIVER IN FLORIDA.  
 
FOR WEDNESDAY NOVEMBER 15 - TUESDAY NOVEMBER 21: COLDER THAN NORMAL  
TEMPERATURES ARE PREDICTED OVER SOUTHERN ALASKA AND THE ALASKA PANHANDLE. GEFS  
OUTPUT INDICATES A MODERATE TO HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES  
(TEMPERATURES IN THE LOWEST 15TH PERCENT OF THE HISTORICAL DISTRIBUTION) FOR  
THE EARLY PORTION OF NEXT WEEK, WITH THE RISK DECREASING THROUGH THE WEEK. SOME  
OF THE COLDER AIR FROM CANADA IS FORECAST TO SPILL SOUTHWARD TOWARD THE  
NORTHERN TIER OF THE CONUS, SO A SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES  
IS INDICATED FROM MONTANA TO THE GREAT LAKES DURING THE MIDDLE OF NEXT WEEK.  
 
THE U.S. DROUGHT MONITOR, VALID ON OCTOBER 31, INDICATES THAT SEVERE TO  
EXCEPTIONAL (D2-D4) DROUGHT COVERS 2.67 PERCENT OF THE CONTINENTAL U.S., WHICH  
IS A SLIGHT INCREASE FROM 2.58 PERCENT LAST WEEK. THE WORST CONDITIONS CONTINUE  
TO BE OVER THE NORTHERN GREAT PLAINS REGION. THE MOST SIGNIFICANT IMPROVEMENTS  
MADE TO THE DROUGHT DEPICTION THIS WEEK WERE OVER THE NORTHEAST, WHERE MUCH OF  
THE REGION RECEIVED MORE THAN 4 INCHES OF RAIN DURING THE PAST WEEK.  
 
FORECASTER: MATTHEW ROSENCRANS  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page