Prognostic Meteorological Discussion
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FXUS21 KWNC 302148
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 30 2015

SYNOPSIS: ON MONDAY, A LOW PRESSURE SYSTEM IS FORECAST TO EXIT THE NORTHEAST. A
STRONG SURFACE HIGH IS EXPECTED TO BUILD INTO THE EASTERN U.S. ON TUESDAY,
WHILE ANOTHER SURFACE HIGH SHIFTS SOUTH FROM CANADA INTO THE NORTH-CENTRAL U.S.
ON WEDNESDAY. AN AREA OF UPPER-LEVEL LOW PRESSURE IS FORECAST TO TRACK FROM
NORTHERN MEXICO TO THE GULF OF MEXICO EARLY IN THE PERIOD. AN AREA OF
UPPER-LEVEL HIGH PRESSURE IS FORECAST TO REMAIN CENTERED OVER CALIFORNIA DURING
THE NEXT TEN DAYS, WHILE THE PACIFIC NORTHWEST EXPERIENCES ONSHORE FLOW. A
STRONG SURFACE HIGH IS FORECAST TO SHIFT EAST FROM THE BERING STRAIT AND BECOME
CENTERED OVER ALASKA BY MID-WEEK.

HAZARDS

HEAVY SNOW FOR PARTS OF THE NORTHEAST, MON, FEB 2.

HEAVY RAIN FOR PARTS OF THE SOUTHEAST, TUE-WED, FEB 3-4.

MUCH BELOW-NORMAL TEMPERATURES ACROSS THE NORTHERN GREAT PLAINS, UPPER
MISSISSIPPI VALLEY, AND GREAT LAKES, MON-WED, FEB 2-4.

PERIODS OF MUCH BELOW-NORMAL TEMPERATURES ACROSS THE EASTERN GREAT LAKES,
NORTHEAST, AND MID-ATLANTIC, TUE-FRI, FEB 3-6.

HIGH WINDS FOR THE NORTHEAST GULF COAST OF ALASKA AND THE ALASKA PANHANDLE,
MON, FEB 2.

A MODERATE RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR THE NORTHEAST, SAT, FEB 7.

A SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR THE EASTERN U.S. AND GULF
COAST, SAT-SUN, FEB 7-8.

SEVERE DROUGHT FOR THE CENTRAL AND SOUTHERN GREAT PLAINS, SOUTHWEST, GREAT
BASIN, CALIFORNIA, AND THE PACIFIC NORTHWEST.

DETAILED SUMMARY

FOR MONDAY FEBRUARY 02 - FRIDAY FEBRUARY 06: AS OF JANUARY 30, 0Z/6Z HIGH
RESOLUTION MODELS INDICATE A LOW PRESSURE SYSTEM TRACKING ACROSS THE
MID-ATLANTIC ON SUNDAY NIGHT AND THEN POTENTIALLY INTENSIFYING AS IT MOVES
OFFSHORE OF THE NORTHEAST ON MONDAY MORNING. MODERATE TO HEAVY SNOW IS EXPECTED
TO THE NORTH OF ITS TRACK FROM SUNDAY NIGHT INTO MONDAY. UNCERTAINTY CONTINUES
ON THE STRENGTH/TRACK OF THE SURFACE LOW AND ASSOCIATED PRECIPITATION
AMOUNTS/TYPES SINCE THE NORTHERN STREAM SHORTWAVE TROUGH IS CURRENTLY ENTERING
WESTERN CANADA. THE RISK OF MODERATE TO HEAVY SNOW (5 INCHES OR MORE) ON SUNDAY
NIGHT INTO MONDAY IS HIGHEST FROM CENTRAL PENNSYLVANIA NORTHEAST TO NEW
ENGLAND. THE 6Z GFS AND 0Z ECMWF ENSEMBLE MEANS ON JANUARY 30 HAVE AROUND 0.50
INCHES (LIQUID EQUIVALENT) ACROSS THESE AREAS. PLEASE REFER TO THE LATEST
STATEMENTS THIS WEEKEND FROM LOCAL NWS OFFICES.



THE UPPER-LEVEL TROUGH THAT SHIFTS SOUTH INTO MEXICO DURING THE WEEKEND IS
FORECAST BY THE HIGH RESOLUTION MODELS TO ENTER THE NORTHERN GULF OF MEXICO
EARLY IN THE PERIOD AND POSSIBLY SPAWN A SURFACE LOW ALONG THE GULF COAST BY
WEDNESDAY. REGARDLESS OF SURFACE LOW DEVELOPMENT, HEAVY RAIN (1-2 INCHES, OR
MORE) IS PREDICTED FOR THE FLORIDA PANHANDLE, NORTHERN FLORIDA PENINSULA, AND
SOUTHEAST GEORGIA ON FEBRUARY 3 AND 4. SEVERE THUNDERSTORMS MAY ALSO DEVELOP
ACROSS THE FLORIDA PENINSULA, BUT MODEL DIFFERENCES ON THE AMPLITUDE OF THE
TROUGH PRECLUDE DESIGNATION OF A SEVERE WEATHER HAZARD AT THIS TIME. FUTURE
FORECASTS OF THIS UPPER-LEVEL TROUGH AND THE POTENTIAL FOR SURFACE LOW
DEVELOPMENT ALONG THE GULF COAST SHOULD BE MONITORED CLOSELY AS IT HAS THE
POTENTIAL TO BRING SNOW TO THE MID-ATLANTIC BY THURSDAY.



ON TUESDAY MORNING, A SURFACE HIGH IS FORECAST OVER THE NORTHEAST WHERE MINIMUM
TEMPERATURES BELOW ZERO ARE PREDICTED. ANOTHER STRONG SURFACE HIGH IS EXPECTED
TO SHIFT SOUTH FROM CANADA AND BUILD EAST ACROSS THE GREAT LAKES AND NORTHEAST
LATER IN THE WEEK. PERIODS OF MUCH-BELOW NORMAL TEMPERATURES (12 DEGREES F OR
MORE) ARE LIKELY ACROSS THE NORTHERN GREAT PLAINS, UPPER MISSISSIPPI VALLEY,
GREAT LAKES, AND NORTHEAST FROM FEBRUARY 2-6.



AN INCREASE IN PRECIPITATION IS FORECAST ACROSS THE PACIFIC NORTHWEST WHERE
LOCALLY HEAVY RAIN IS POSSIBLE ACROSS COASTAL WASHINGTON. SNOW LEVELS ARE
EXPECTED TO BE RELATIVELY HIGH FOR THE CASCADES. RAINFALL AND SNOWFALL AMOUNTS
ARE NOT EXPECTED TO REACH HAZARDS CRITERIA AT THIS TIME.



A TIGHT PRESSURE GRADIENT IS EXPECTED TO RESULT IN HIGH WINDS FOR THE INTERIOR
MOUNTAINS OF THE ALASKA PANHANDLE AND NORTHEAST GULF COAST NEAR YAKUTAT ON
MONDAY. THE GEFS MODEL INDICATES SURFACE TEMPERATURES IN THE LOWEST 20TH
PERCENTILE ACROSS WESTERN AND SOUTHWESTERN ALASKA FROM THURSDAY TO SATURDAY.
MODEL OUTPUTS AND TRENDS WILL NEED TO BE MONITORED TO SEE IF CERTAINTY ABOUT
THE INTENSITY OF THE COLD INCREASES BEYOND HAZARDOUS THRESHOLDS.

FOR SATURDAY FEBRUARY 07 - FRIDAY FEBRUARY 13: EARLY IN WEEK-2, AN AMPLIFIED
TROUGH SUPPORTS A SLIGHT TO MODERATE RISK OF MUCH BELOW-NORMAL TEMPERATURES
ACROSS THE EASTERN U.S. THE LONGWAVE PATTERN DEPICTED BY THE GFS AND ECMWF
ENSEMBLE MEANS FAVOR ABOVE-MEDIAN PRECIPITATION ACROSS THE PACIFIC NORTHWEST
WITH RELATIVELY DRY CONDITIONS PERSISTING ACROSS SOUTHERN CALIFORNIA.
PRECIPITATION AMOUNTS ACROSS NORTHERN CALIFORNIA ARE MORE UNCERTAIN AS MODEL
SOLUTIONS VARY ON HOW FAR SOUTH THE ONSHORE FLOW EXTENDS.



THE MOST RECENT U.S. DROUGHT MONITOR, VALID ON JANUARY 27, 2015 INDICATES A
VERY SLIGHT DECREASE IN THE AREAL COVERAGE OF SEVERE TO EXCEPTIONAL DROUGHT (D2
TO D4) FROM 16.97 TO 16.83 PERCENT ACROSS THE CONTINENTAL U.S. 40 PERCENT OF
CALIFORNIA REMAINS DESIGNATED IN THE EXCEPTIONAL DROUGHT CATEGORY.

FORECASTER: BRAD PUGH

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