Valid Friday, February 17, 2012 to Tuesday, February 28, 2012

Summary of Forecasts and Hazards

US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EST FEBRUARY 14 2012

SYNOPSIS: THE ASSESSMENT PERIOD IS EXPECTED TO BEGIN WITH A LOW-PRESSURE CENTER OVER NEW
ENGLAND, HIGH PRESSURE STRETCHED ACROSS THE INTERIOR CONUS, AND A STATIONARY
FRONT ACROSS THE SOUTHEAST. DURING THE WEEKEND, AN UPPER-LEVEL, LOW-PRESSURE
SYSTEM IS EXPECTED TO MOVE ACROSS THE WESTERN CONUS AND CONTRIBUTE TO THE
DEVELOPMENT OF A MORE ROBUST SYSTEM ACROSS THE GREAT PLAINS DURING THE EARLY
PORTIONS OF NEXT WEEK. ALONG THE FRONT LOCATED ACROSS THE SOUTHEAST, A LOW-
PRESSURE SYSTEM IS EXPECTED TO DEVELOP AND MOVE EASTWARD. THE RESULTING PATTERN
SHOULD FEATURE FAST MOVING SYSTEMS AND SEASONABLE TEMPERATURES. ACROSS ALASKA,
THE FOCUS OF THE ACTIVE WEATHER SHOULD BE IN THE SOUTHWESTERN PART OF THE STATE.

HAZARDS

• HEAVY LAKE-EFFECT SNOW ON FEBRUARY 17.
• HEAVY RAIN FOR PARTS OF THE GULF COAST AND SOUTHEAST, FEBRUARY, 18-19.
• HIGH WINDS ACROSS THE SOUTHWEST, FEBRUARY 19-20.
• HIGH WINDS ACROSS SOUTHWEST ALASKA, FEBRUARY 19.
• SEVERE DROUGHT FOR PARTS OF THE CENTRAL AND SOUTHERN GREAT PLAINS, SOUTHWEST,
• SOUTHEAST, WESTERN CORN BELT, NORTHEAST MINNESOTA, AND HAWAII.

DETAILED SUMMARY

FOR FRIDAY FEBRUARY 17 - TUESDAY FEBRUARY 21: A LOW-PRESSURE SYSTEM IS FORECAST TO BE LOCATED ACROSS THE NORTHEAST AT THE
START OF THE ASSESSMENT PERIOD. WINDS BEHIND THAT SYSTEM ARE FORECAST TO SUPPORT
LAKE EFFECT SNOWS DURING FRIDAY. SNOWS ARE LIKELY TO IMPACT THE CENTRAL
APPALACHIANS, GREAT LAKES, AND NORTHEAST UNTIL ABATING LATER FRIDAY AND EARLY
SATURDAY.

ON THE SOUTHERN FLANK OF THE STORM SYSTEM, HEAVY RAINS ARE LIKELY OVER THE
SOUTHEAST. SOME STRONG CONVECTION WITH ISOLATED SEVERE WEATHER IS LIKELY,
ESPECIALLY IN THE IMMEDIATE VICINITY OF THE GULF COAST, ACROSS GEORGIA, AND OVER
NORTHERN FLORIDA. RAINFALL TOTALS ARE EXPECTED TO EXCEED 2 INCHES IN 48 HOURS
ACROSS NORTHERN FLORIDA.

THE COLD FRONT ASSOCIATED WITH THIS LOW-PRESSURE SYSTEM IS EXPECTED TO STALL
OVER FLORIDA. THIS BOUNDARY IS LIKELY TO BECOME A FOCAL POINT FOR RAINS DURING
THE WEEKEND AS ANOTHER, ALBEIT WEAKER, LOW-PRESSURE SYSTEM IS FORECAST TO
DEVELOP OVER THE NORTHERN GULF OF MEXICO AND MOVE ACROSS NORTHERN FLORIDA.
WIDESPREAD RAINS IN EXCESS OF 2 INCHES ARE FORECAST BY MOST MODELS. ALONG THE
NORTHERN FRINGES OF THE RAINFALL, ACROSS THE MID-ATLANTIC, SOME MIXED
PRECIPITATION IS LIKELY DURING LATE SUNDAY AND EARLY MONDAY.

ALONG WITH THE WEAK LOW-PRESSURE SYSTEM, ISOLATED SEVERE WEATHER IS LIKELY OVER
FLORIDA DURING SATURDAY, ALTHOUGH EXACT TIMING AND LOCATION WITH RESPECT TO THE
TRACK OF THE LOW-PRESSURE CENTER (NORTH FLORIDA VERSUS CENTRAL FLORIDA)
PROHIBITS THE INCLUSION OF A HAZARD AT THIS TIME.

A TROUGH IS EXPECTED TO MOVE SOUTHWARD ALONG THE PACIFIC COAST DURING THE
WEEKEND. MOUNTAIN SNOWS AND COASTAL RAINS ARE LIKELY FROM WASHINGTON TO CENTRAL
CALIFORNIA. COASTAL OREGON IS LIKELY TO RECEIVE THE MOST RAINFALL, ALTHOUGH
TOTALS ARE NOT EXPECTED TO BE ABNORMALLY HIGH FOR THIS TIME OF YEAR.

AS THE SYSTEM MOVES EASTWARD, SNOWS ACROSS THE INTERMOUNTAIN WEST ARE LIKELY TO
START THE WEEK. SNOWFALL AMOUNTS ARE FORECAST TO VARY WIDELY, WITH ISOLATED
AREAS ACROSS UTAH, NEVADA, AND COLORADO RECEIVING IN EXCESS OF 6 INCHES OF SNOW.
THE MODELS (GFS AND ECMWF) HAVE SLIGHTLY DIFFERENT TRACKS FOR THE LOW-PRESSURE
SYSTEM, SO NO HAZARD IS DEPICTED DUE TO THE UNCERTAINTY OF THE EXACT LOCATIONS
OF THE HIGHEST SNOWFALL TOTALS.

SOUTHWESTERN ALASKA IS FORECAST TO EXPERIENCE THE MOST ACTIVE WEATHER ACROSS THE
STATE DURING THE NEXT WEEK. ACCORDING TO THE LATEST SOLUTIONS FROM THE
WAVEWATCH3 MODEL, WAVE HEIGHTS ARE EXPECTED TO BRIEFLY EXCEED 20 FEET TO THE
SOUTH OF THE ALEUTIANS. THE WIND THAT IS FORECAST TO SUPPORT THOSE WAVES IS
EXPECTED TO EXCEED HAZARDOUS THRESHOLDS DURING THE WEEKEND.

FOR WEDNESDAY FEBRUARY 22 - TUESDAY FEBRUARY 28: DURING THE SECOND WEEK OF THE ASSESSMENT PERIOD, TROUGHING AND BELOW-NORMAL
HEIGHTS ARE EXPECTED ACROSS THE CENTRAL PORTIONS OF THE CONUS WITH ABOVE-NORMAL
HEIGHTS ALONG THE IMMEIDATE WEST COAST. THIS PATTERN FAVORS WET CONDITIONS
ACROSS THE PACIFIC NORTHWEST AND FROM THE CENTRAL GULF COAST TO THE GREAT LAKES.

SPECIFICALLY, THE GFS ENSEMBLE MEAN AND THE ECMWF ENSEMBLE MEAN BOTH DEPICT THE
DEVELOPMENT OF A LOW-PRESSURE SYSTEM OVER THE CENTRAL GREAT PLAINS. THE TRACK
OF THE LOW-PRESSURE SYSTEM AND THE INTENSITY OF THE SYSTEM ARE STILL UNCERTAIN.
THE TWO ENSEMBLE MEANS DO INDICATE THE POTENTIAL FOR A LARGE AREA OF
FROZEN/FREEZING PRECIPITATION FROM THE CENTRAL GREAT PLAINS TO THE UPPER GREAT
LAKES DURING WEDNESDAY.

LATER NEXT WEEK, THE ENSEMBLE MEANS FROM THE GFS AND THE ECMWF INDICATE
TROUGHING OVER THE CENTER OF THE CONUS WITH SIGNIFICANT RAINFALL OVER THE
SOUTHEAST. AT THIS TIME, THE FORECASTS ARE NOT IN EXCESS OF HAZARDS THRESHOLDS.

DROUGHT CONDITIONS ARE EXPECTED TO CONTINUE OVER THE CENTRAL AND SOUTHERN GREAT
PLAINS, SOUTHWEST, SOUTHEAST, WESTERN CORN BELT, NORTHEAST MINNESOTA, AND
HAWAII. SOME RELIEF IS EXPECTED ACROSS THE NORTHWEST.

FORECASTER: MATTHEW ROSENCRANS

$$

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