Prognostic Meteorological Discussion
Issued by NWS

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FXUS21 KWNC 231904
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MARCH 23 2017

SYNOPSIS: SEVERAL WEAK LOW PRESSURE SYSTEMS ARE EXPECTED TO TRACK NORTHEASTWARD
FROM THE SOUTHERN HIGH PLAINS TO THE NORTHEAST DURING MOST OF THE OUTLOOK
PERIOD. MOST OF THE HAZARDOUS WEATHER CONDITIONS ARE PREDICTED TO BE OVER THE
SOUTHERN GREAT PLAINS, THE LOWER MISSISSIPPI VALLEY, AND THE NORTHEAST. THE
ANTICIPATED PASSAGE OF SEVERAL FRONTAL SYSTEMS ACROSS THE WEST DURING THIS
OUTLOOK PERIOD MAY ALSO BRING ADDITIONAL HAZARDS, PRIMARILY TO THE NORTHWESTERN
CONTIGUOUS U.S. THE NORTHERN PORTIONS OF ALASKA ARE PREDICTED TO BE DOMINATED
BY SURFACE HIGH PRESSURE, WHILE SOUTHERN AREAS ARE FORECAST TO BE AFFECTED BY
THE OCCASIONAL PASSAGE OF WEAK LOW PRESSURE AREAS.

HAZARDS

SEVERE WEATHER FOR PARTS OF THE SOUTHERN PLAINS, SUN, MAR 26.

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

ENHANCED RISK OF CRITICAL WILDFIRE CONDITIONS FOR PARTS OF THE FAR SOUTHERN
HIGH PLAINS REGION, SUN, MAR 26.

FREEZING RAIN/SLEET FOR NORTHERN PORTIONS OF LOWER MICHIGAN, NORTHERN NEW YORK,
AND MUCH OF NEW ENGLAND, SUN-MON, MAR 26-27.

PERIODS OF LOCALLY HEAVY RAIN FOR PARTS OF THE SOUTHERN PLAINS, WED-THU, MAR
29-30.

PERIODS OF LOCALLY HEAVY RAIN FOR THE I-95 CORRIDOR FROM NEAR THE NATION`S
CAPITAL NORTHEASTWARD TO SOUTHERN NEW HAMPSHIRE, SUN-MON, MAR 26-27.

HEAVY PRECIPITATION (RAIN AND MOUNTAIN SNOW) FOR THE PACIFIC NORTHWEST AND FAR
NORTHWESTERN CALIFORNIA, SUN-MON, MAR 26-27.

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

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, FRI-SAT, MAR 31-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 SUNDAY MARCH 26 - THURSDAY MARCH 30: DURING THIS PERIOD, SEVERAL LOW
PRESSURE SYSTEMS ARE FORECAST TO DEVELOP OVER THE SOUTHERN HIGH PLAINS REGION,
THEN TRACK NORTHEASTWARD ACROSS THE MIDDLE MISSISSIPPI VALLEY AND MIDWEST, AND
INTO THE NORTHEAST. EACH OF THESE LOWS IS EXPECTED TO BE ACCOMPANIED BY SEVERAL
HAZARDS. AS THE FIRST SYSTEM MOVES ACROSS THE OHIO VALLEY AND NORTHEAST, AN
AREA OF LOCALLY HEAVY RAIN (1-2 INCHES) IS FORECAST ACROSS THE I-95 CORRIDOR
FROM NEAR THE NATION`S CAPITAL NORTHEASTWARD TO SOUTHERN NEW HAMPSHIRE, ON
MARCH 26-27. AT THE SAME TIME, A WINTRY MIX OF RAIN, FREEZING RAIN, SLEET, AND
SNOW IS EXPECTED TO DEVELOP FROM NORTHERN LOWER MICHIGAN EASTWARD ACROSS
NORTHERN NEW YORK AND MUCH OF NEW ENGLAND.



THE SECOND IN A CONTINUING SERIES OF LOW PRESSURE SYSTEMS IS ANTICIPATED TO
MOVE ACROSS THE SOUTH-CENTRAL CONUS ON MARCH 26-27. THERE IS AN ELEVATED RISK
OF CRITICAL WILDFIRE CONDITIONS ON MARCH 26TH ACROSS FAR SOUTHERN PORTIONS OF
THE SOUTHERN HIGH PLAINS REGION, FROM ABOUT EL PASO TO SAN ANGELO, TEXAS.
STRONG WINDS ALOFT AHEAD OF THE ASSOCIATED 500-HPA SHORTWAVE, DEEP
BOUNDARY-LAYER MIXING, A TIGHT SURFACE PRESSURE GRADIENT, ABOVE-AVERAGE
TEMPERATURES, AND RELATIVE HUMIDITY VALUES BELOW 15 PERCENT ARE ALL EXPECTED TO
CONTRIBUTE TO THIS ELEVATED RISK OF WILDFIRES. ON THE SAME DAY, OVER THE
SOUTHERN LOWER PLAINS, THERE IS A SIGNIFICANT RISK OF SEVERE WEATHER BREAKING
OUT IN ADVANCE OF A DRYLINE, AS IT MIXES EASTWARD ACROSS THE SOUTHERN PLAINS
DURING THE DAYTIME. THE FOLLOWING DAY, MARCH 27TH, ANOTHER ROUND OF SEVERE
WEATHER IS EXPECTED TO DEVELOP FARTHER EAST, OVER THE LOWER MISSISSIPPI AND
LOWER TENNESSEE VALLEYS. YET ANOTHER LOW PRESSURE SYSTEM IS FORECAST TO MOVE
THROUGH THE SOUTHERN STREAM ACROSS THE SOUTHERN PLAINS REGION AND LOWER
MISSISSIPPI VALLEY, BRINGING PERIODS OF LOCALLY HEAVY RAINFALL TO PORTIONS OF
OKLAHOMA AND TEXAS ON MARCH 29-30. THOUGH STRONG TO SEVERE THUNDERSTORMS ARE
AGAIN POSSIBLE, THERE IS TOO MUCH UNCERTAINTY BETWEEN THE ECMWF AND GFS
SOLUTIONS AT THIS TIME TO JUSTIFY THE DEPICTION OF A SEVERE WEATHER AREA ON THE
MAP. THE GFS MODEL SUGGESTS THE POSSIBILITY OF SEVERE WEATHER RECURRING IN THE
SAME GENERAL AREA (SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY, GENERALLY
CENTERED ON THE ARKLATEX REGION), WHILE THE ECMWF MODEL SUGGESTS THE SEVERE
WEATHER RISK AREA MAY EXTEND NORTHWARD TO INCLUDE PORTIONS OF THE CENTRAL
PLAINS AND MIDDLE MISSISSIPPI VALLEY.



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 WESTERN WASHINGTON, WESTERN OREGON, AND FAR NORTHWESTERN CALIFORNIA, FOR
LIQUID EQUIVALENT PRECIPITATION AMOUNTS OF ABOUT 1.5-2.5 INCHES. USING 2 INCHES
AS THE APPROXIMATE THRESHOLD FOR SEPARATING HAZARDOUS AMOUNTS OF PRECIPITATION
FROM NON-HAZARDOUS AMOUNTS, IT IS CLEAR THIS IS CONSIDERED A MARGINAL HAZARD AT
BEST.



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



IN ALASKA, NO HAZARDS ARE POSTED AT THIS TIME DUE TO SURFACE HIGH PRESSURE
PREDICTED ACROSS THE NORTHERN PART OF THE STATE, AND WEAK LOW PRESSURE SYSTEMS
MOVING ACROSS THE SOUTHERN PART OF THE STATE. ONE VERY LOCALIZED ISSUE BEING
CONSIDERED IS THE POTENTIAL FOR HEAVY PRECIPITATION (2 INCHES OR MORE, LIQUID
EQUIVALENT, DURING A 24-HOUR PERIOD) FOR WESTERN SECTIONS OF PRINCE WILLIAM
SOUND (INCLUDING COLLEGE FJORD) AND THE EASTERN KENAI PENINSULA ON MARCH 30TH.
THIS IS DUE TO AN APPROACHING LOW PRESSURE SYSTEM AND SUSTAINED SOUTHEASTERLY
FLOW FORCING MOISTURE TO RISE UP THE SLOPES OF THE CHUGACH MOUNTAIN RANGE, AND
CONDENSE.

FOR FRIDAY MARCH 31 - THURSDAY APRIL 06: 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, THOUGH AS DISCUSSED IN THE PREVIOUS
SECTION, THE MAIN UNCERTAINTY IS THE SPATIAL EXTENT OF A POSSIBLE SEVERE
WEATHER OUTBREAK.



ON MARCH 31-APRIL 1, 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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