Prognostic Meteorological Discussion
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FXUS21 KWNC 291824
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MARCH 29 2017

SYNOPSIS: A LOW PRESSURE SYSTEM IS EXPECTED TO IMPACT THE ROCKIES, SOUTHERN
PLAINS, AND EASTERN U.S. THIS WEEKEND THROUGH EARLY NEXT WEEK. THE NORTHWEST
U.S. IS EXPECTED TO SEE MORE ACTIVE WEATHER LATE IN WEEK-1 AND EARLY IN WEEK-2,
WITH WARMER-THAN-NORMAL TEMPERATURES WIDELY FAVORED OVER MOST OF THE U.S.
DURING THE ENTIRE PERIOD. THE SOUTHWEST AND SOUTHERN PLAINS ARE EXPECTED TO
BECOME LESS ACTIVE LATE IN WEEK-1 AND DURING WEEK-2. A STRONG AREA OF
UPPER-LEVEL LOW PRESSURE IS EXPECTED TO BRING ACTIVE WEATHER TO PARTS OF
SOUTHERN AND SOUTHEASTERN ALASKA EARLY IN THE PERIOD.

HAZARDS

HEAVY RAIN AND SNOW FOR PARTS OF EASTERN AND CENTRAL COLORADO, SAT, APR 1.

SEVERE WEATHER FOR PARTS OF THE SOUTHERN PLAINS, SAT, APR 1.

SEVERE WEATHER FOR PARTS OF THE SOUTHERN PLAINS, WESTERN GULF COAST, AND LOWER
MISSISSIPPI VALLEY, SUN, APR 2.

HEAVY RAIN FOR PARTS OF THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY,
SAT-SUN, APR 1-2.

HEAVY RAIN FOR PARTS OF THE SOUTHEAST AND MID-ATLANTIC, MON-TUE, APR 3-4.

FLOODING IS POSSIBLE, LIKELY, OR IMMINENT/OCCURRING OVER PARTS OF THE PACIFIC
NORTHWEST, NORTHERN AND CENTRAL INTERMOUNTAIN REGION, THE NORTHERN ROCKIES, AND
THE NORTHERN PLAINS.

SEVERE DROUGHT ACROSS PARTS OF ARIZONA, CALIFORNIA, THE CENTRAL AND SOUTHERN
GREAT PLAINS, ARKANSAS, MISSOURI, AND THE EASTERN U.S.

DETAILED SUMMARY

FOR SATURDAY APRIL 01 - WEDNESDAY APRIL 05: ON SATURDAY AND SUNDAY, A DEEP
UPPER-LEVEL LOW IS FORECAST TO MOVE FROM THE INTERIOR WEST INTO THE CENTRAL
CONUS, BRINGING HEAVY RAIN AND SNOW TO PARTS OF THE FRONT RANGE IN COLORADO (>1
INCHES LIQUID EQUIVALENT IN 48 HOURS) AND THE THREAT OF HEAVY RAIN AND SEVERE
WEATHER TO PARTS OF THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. THE HEAVY
RAIN THREAT SHIFTS EASTWARD ACROSS THE SOUTHERN TIER OF THE U.S. AND EXTENDS
NORTHEASTWARD TO THE MID-ATLANTIC BY TUESDAY. THE HEAVY RAIN HAZARD IS DEPICTED
WHERE MORE CONVECTIVE PRECIPITATION COULD LEAD TO ENHANCED LOCAL RAINFALL
TOTALS. FARTHER NORTHWEST, OVER THE OHIO VALLEY FOR EXAMPLE, MODERATE
STRATIFORM RAINFALL AMOUNTS ARE EXPECTED. ISOLATED SEVERE WEATHER IS POSSIBLE
ACROSS THE SOUTHEAST ESPECIALLY ON MONDAY, BUT DIMINISHING UPPER-LEVEL FORCING
AND MODEL UNCERTAINTY PRECLUDE DEPICTION OF A SEVERE WEATHER SHAPE AT THIS TIME.



OVER PARTS OF THE SOUTHWEST, CRITICAL FIRE WEATHER IS POSSIBLE DURING MUCH OF
THE PERIOD, THOUGH PROBABILITIES FALL BELOW THAT REQUIRED FOR A HAZARD
DEPICTION ON THE MAP.



ANOTHER UPPER-LEVEL LOW IS FORECAST TO MOVE INTO THE ROCKIES EARLY NEXT WEEK,
THOUGH WITH REDUCED AMPLITUDE COMPARED TO THE PRECEDING SYSTEMS WHILE TAKING A
MORE NORTHERN TRACK INTO THE CENTRAL PLAINS. AT THIS TIME THERE ARE NO HAZARDS
TO DENOTE ASSOCIATED WITH THIS SYSTEM, THOUGH THIS IS LIKELY TO BRING MORE
ACTIVE WEATHER TO PARTS OF THE CENTRAL PLAINS AND MIDWEST DURING THE MIDDLE OF
NEXT WEEK.



ANOMALOUS UPPER-LEVEL TROUGHING IS FORECAST NEAR THE ALEUTIANS AND OVER PARTS
OF THE NORTHEASTERN PACIFIC EARLY IN THE PERIOD, WHICH COULD BRING ACTIVE
WEATHER TO PARTS OF SOUTHERN AND SOUTHEASTERN ALASKA THIS WEEKEND. HOWEVER,
CURRENT FORECAST PRECIPITATION AMOUNTS FALL BELOW THE HAZARDOUS CRITERIA. AS
THIS UPPER-LEVEL TROUGH PROGRESSES EASTWARD TOWARD THE WEST COAST, THE THREAT
OF HEAVY PRECIPITATION INCREASES FOR THE PACIFIC NORTHWEST BY THE END OF THE
PERIOD, CONTINUING INTO WEEK-2. AT THIS TIME, HOWEVER, NO CATEGORICAL HAZARDS
CAN BE DENOTED.



FLOODING IS POSSIBLE, LIKELY, OR OCCURRING/IMMINENT ACROSS PARTS OF THE PACIFIC
NORTHWEST, THE NORTHERN AND CENTRAL INTERMOUNTAIN REGION, AND THE NORTHERN
ROCKIES.

FOR THURSDAY APRIL 06 - WEDNESDAY APRIL 12: DURING WEEK-2, A MORE AMPLIFIED
WAVE PATTERN IS FORECAST WITH A DEEP ANOMALOUS TROUGH OVER THE NORTHEASTERN
PACIFIC, RIDGING OVER THE WEST-CENTRAL CONUS, AND ANOMALOUS TROUGHING NEAR THE
EAST COAST. WHILE WARMER-THAN-NORMAL TEMPERATURES ARE FORECAST OVER NEARLY THE
ENTIRE FORECAST DOMAIN AGAIN TODAY, PROBABILITIES ARE SLIGHTLY REDUCED OVER THE
WEST COAST AND THE EASTERN CONUS GIVEN THE HIGHER AMPLITUDE WAVE PATTERN AND
INCREASED ODDS OF COOLER CANADIAN AIR MASSES AFFECTING PARTS OF THE CONUS.



THE STORM TRACK DURING WEEK-2 IS EXPECTED TO EXTEND FROM THE PACIFIC NORTHWEST
ACROSS THE NORTHERN TIER OF THE CONUS, LEADING TO A LESS ACTIVE PATTERN THAN IS
FORECAST OVER THE SHORT TERM FOR MUCH OF THE SOUTHERN PLAINS AND PARTS OF THE
SOUTHEAST.



ACCORDING TO THE U.S. DROUGHT MONITOR RELEASED ON MARCH 23RD (USING DATA
THROUGH 8AM EASTERN TIME, MARCH 21ST), CHANGES COMPARED TO THE PREVIOUS WEEK
INCLUDED ONE-CLASS DEGRADATION ACROSS PARTS OF THE SOUTHERN TIER OF STATES FROM
NEW MEXICO TO SOUTH CAROLINA, PARTS OF OKLAHOMA AND KANSAS, AND HAWAII.
ONE-CLASS IMPROVEMENTS IN DROUGHT CATEGORY WERE PRIMARILY FOCUSED ON THE
NORTHEAST AND MID-ATLANTIC, TENNESSEE, NORTHERN ALABAMA, AND EASTERN PORTIONS
OF PUERTO RICO. NO CHANGES TO THE DROUGHT DEPICTION WERE MADE IN ALASKA.
COVERAGE OF SEVERE, OR GREATER INTENSITY, DROUGHT THROUGHOUT THE CONUS
DECREASED SLIGHTLY FROM 3.95 LAST WEEK TO 3.74 PERCENT THIS WEEK.

FORECASTER: STEPHEN BAXTER

$$



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