Prognostic Meteorological Discussion
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FXUS21 KWNC 241925
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MARCH 24 2017

SYNOPSIS: DURING THE FIRST FEW DAYS OF THE OUTLOOK PERIOD, SEVERAL WAVES OF LOW
PRESSURE ARE PREDICTED TO TRACK NORTHEASTWARD ALONG A COLD FRONT THAT IS
INITIALLY FORECAST TO EXTEND FROM THE SOUTHERN PLAINS TO THE EASTERN GREAT
LAKES REGION. THE FRONT IS EXPECTED TO STALL AS IT REACHES THE DEEP SOUTH
SEVERAL DAYS LATER. ON MARCH 30TH, THIS FRONT IS ANTICIPATED TO BEGIN MOVING
NORTHWARD AS A WARM FRONT, WHICH EXTENDS WESTWARD TO A DEVELOPING LOW PRESSURE
CENTER OVER THE SOUTHERN PLAINS. THIS DEVELOPING LOW IS THEN FORECAST TO TRACK
NORTHEASTWARD TOWARDS THE OHIO VALLEY AND EASTERN GREAT LAKES REGION. THE
ANTICIPATED PASSAGE OF SEVERAL FRONTAL SYSTEMS ACROSS THE WEST DURING THIS
OUTLOOK PERIOD IS EXPECTED TO BRING ADDITIONAL PRECIPITATION, ESPECIALLY TO THE
PACIFIC NORTHWEST. IN ALASKA, SEVERAL AREAS OF WEAK LOW PRESSURE ARE PROJECTED
TO INFLUENCE THE SOUTHERN PORTIONS OF THE STATE. A MORE SIGNIFICANT STORM
SYSTEM MAY AFFECT THE ALEUTIANS AND ALASKA PENINSULA ABOUT A WEEK FROM NOW.

HAZARDS

SEVERE WEATHER FOR PARTS OF THE LOWER MISSISSIPPI AND LOWER TENNESSEE VALLEYS,
MON, MAR 27.

SEVERE WEATHER FOR WEST-CENTRAL TEXAS AND NEARBY PARTS OF EXTREME SOUTHERN
OKLAHOMA, TUE, MAR 28.

SEVERE WEATHER FOR EASTERN PORTIONS OF THE SOUTHERN PLAINS, AND THE LOWER
MISSISSIPPI VALLEY, WED, MAR 29.

PERIODS OF LOCALLY HEAVY RAIN FOR CENTRAL AND SOUTHERN PORTIONS OF BOTH THE
GREAT PLAINS AND MISSISSIPPI VALLEY, EXTENDING EASTWARD INTO ALABAMA, MON-THU,
MAR 27-30.

MIXED PRECIPITATION (RAIN, FREEZING RAIN, SLEET AND SNOW) FOR MUCH OF NEW
ENGLAND, MON, MAR 27.

HEAVY PRECIPITATION (RAIN AND MOUNTAIN SNOW) FOR THE PACIFIC NORTHWEST,
MON-TUE, MAR 27-28.

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

HEAVY RAIN FOR EASTERN PORTIONS OF BOTH OKLAHOMA AND TEXAS, AND THE LOWER
MISSISSIPPI VALLEY, SAT-SUN, APR 1-2.

SLIGHT CHANCE OF MUCH ABOVE-NORMAL TEMPERATURES FROM THE LOWER MISSISSIPPI
VALLEY EASTWARD TO THE SOUTHERN ATLANTIC COAST, SAT, APR 1.

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

DETAILED SUMMARY

FOR MONDAY MARCH 27 - FRIDAY MARCH 31: AT THE START OF THE PERIOD, A COLD FRONT
IS PREDICTED TO STRETCH SOUTHWESTWARD FROM A LOW PRESSURE CENTER OVER THE
EASTERN GREAT LAKES REGION TO THE SOUTHERN GREAT PLAINS. A WARM FRONT IS
FORECAST TO EXTEND EASTWARD FROM THE SURFACE LOW ACROSS THE NORTHEAST CONUS.
ANOTHER LOW PRESSURE CENTER IS INITIALLY PREDICTED ON THE COLD FRONT IN THE
VICINITY OF THE OZARK MOUNTAINS. THIS COMPLEX FRONTAL SYSTEM IS ANTICIPATED TO
BRING SEVERAL WEATHER-RELATED HAZARDS, THE MOST SERIOUS OF WHICH INCLUDES
MULTIPLE SEVERE THUNDERSTORM OUTBREAKS ACROSS THE SOUTHERN PLAINS, LOWER
MISSISSIPPI VALLEY, AND LOWER TENNESSEE VALLEY DURING A THREE-DAY PERIOD.
CHRONOLOGICALLY, THE FIRST HIGHLIGHTED AREA OF SEVERE WEATHER IS APPLICABLE FOR
THE LOWER MISSISSIPPI AND LOWER TENNESSEE VALLEYS ON MONDAY, MARCH 27TH. THE
STORM PREDICTION CENTER (SPC) IN OKLAHOMA EXPECTS AN AXIS OF INSTABILITY NEAR
THE SOUTHERN PORTION OF THE MISSISSIPPI RIVER, AND DEEP-LAYER WIND SHEAR
ASSOCIATED WITH A BELT OF STRONGER 500-HPA FLOW ROUNDING THE BASE OF THE UPPER
TROUGH. THESE CONDITIONS ARE THOUGHT TO BE SUFFICIENT FOR ISOLATED AREAS OF
SEVERE WEATHER. ON TUESDAY, MARCH 28TH, LOW-LEVEL GULF MOISTURE IS ANTICIPATED
TO STREAM NORTHWARD ACROSS THE SOUTHERN PLAINS AHEAD OF AN EASTWARD-ADVANCING
DRYLINE. ISOLATED SEVERE WEATHER COVERAGE IS AGAIN ANTICIPATED DURING THE
AFTERNOON, THIS TIME ACROSS WEST-CENTRAL TEXAS AND ADJACENT PARTS OF OKLAHOMA.
THE SPATIAL COVERAGE OF SEVERE THUNDERSTORMS IS EXPECTED TO INCREASE LATE IN
THE DAY AND EVENING AS THE 500-HPA LOW AND TROUGH APPROACH THE AREA. MODERATE
INSTABILITY AND STRONG DEEP-LAYER SHEAR ARE FORECAST TO BE IN PLACE. IN
ADDITION, A WELL-DEVELOPED LOW-LEVEL JET SHOULD MAINTAIN AN ORGANIZED SEVERE
WEATHER THREAT LATE TUESDAY NIGHT INTO WEDNESDAY, MARCH 29TH. PREDICTED HAZARDS
INCLUDE LARGE HAIL, WIND DAMAGE, AND SOME TORNADOES, AS AN EXPECTED SQUALL LINE
ORGANIZES AND MOVES ACROSS THE SOUTHERN PLAINS FROM TUESDAY EVENING INTO
WEDNESDAY AFTERNOON. PERIODS OF HEAVY RAINFALL ARE ALSO PREDICTED ACROSS
CENTRAL AND SOUTHERN PORTIONS OF BOTH THE GREAT PLAINS AND MISSISSIPPI VALLEY,
EXTENDING EASTWARD INTO ALABAMA, FROM MARCH 27-30. PRECIPITATION AMOUNTS DURING
THIS 4-DAY PERIOD ARE EXPECTED TO RANGE FROM 2-6 INCHES.



EARLY IN THIS PERIOD, ON MARCH 27TH, THERE IS AN INCREASED RISK OF MIXED
PRECIPITATION (RAIN, FREEZING RAIN, SLEET AND SNOW) FOR MUCH OF NEW ENGLAND,
NORTH OF A PREDICTED WARM FRONT.



PACIFIC STORM SYSTEMS ARE FORECAST TO MOVE ACROSS THE WEST COAST STATES DURING
THIS PERIOD. A HEAVY PRECIPITATION (RAIN AND MOUNTAIN SNOW) HAZARD IS POSTED
FOR THE PACIFIC NORTHWEST FOR LIQUID EQUIVALENT PRECIPITATION AMOUNTS OF ABOUT
2.0-3.5 INCHES.



FLOODING IS POSSIBLE, LIKELY, OR OCCURRING/IMMINENT ACROSS PARTS OF THE PACIFIC
NORTHWEST, THE NORTHERN AND CENTRAL INTERMOUNTAIN REGION, AND THE NORTHERN
ROCKIES. THIS IS DUE TO UNSEASONABLY WARM TEMPERATURES COUPLED WITH RAINFALL
DURING MID-MARCH.



A SIGNIFICANT CYCLONIC SYSTEM MAY APPROACH THE ALEUTIANS AND ALASKA PENINSULA
FROM THE SOUTHWEST LATE IN THIS PERIOD. HOWEVER, SUBSTANTIAL DISAGREEMENTS
BETWEEN THE ECMWF AND GFS MODELS REGARDING THE FORECAST PATH OF THIS SYSTEM
PRECLUDE THE SPECIFICATION OF HAZARDOUS AREAS ON THE MAP AT THIS TIME.

FOR SATURDAY APRIL 01 - FRIDAY APRIL 07: AN AREA OF HEAVY RAIN IS FORECAST OVER
EASTERN PORTIONS OF BOTH OKLAHOMA AND TEXAS, AND OVER THE LOWER MISSISSIPPI
VALLEY, FROM APRIL 1-2. THIS IS IN RESPONSE TO A 500-HPA TROUGH EXPECTED TO
APPROACH THIS AREA FROM THE WEST. THERE IS ALSO THE POTENTIAL FOR STRONG TO
SEVERE THUNDERSTORMS TO DEVELOP ONCE AGAIN IN THIS GENERAL AREA, BUT THERE IS
NOT ENOUGH CONFIDENCE AT THIS TIME TO WARRANT THE DEPICTION OF A SEVERE WEATHER
REGION.



ON APRIL 1ST, THERE IS A SLIGHT CHANCE (20-PERCENT) OF MUCH ABOVE-NORMAL
TEMPERATURES FROM THE LOWER MISSISSIPPI VALLEY EASTWARD TO THE SOUTHERN
ATLANTIC COAST. WITHIN THIS AREA, TEMPERATURES ARE EXPECTED TO REACH THE 85TH
PERCENTILE (OR HIGHER) OF THE HISTORICAL DISTRIBUTION. FOR MOST AREAS, HIGH
TEMPERATURES ARE FORECAST TO REACH THE MID-UPPER 80`S, WHILE A FEW LOCALES MAY
PUSH 90 DEG F.



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: ANTHONY ARTUSA

$$




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