Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 030530
SWODY2
SPC AC 030529

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1229 AM CDT SUN MAY 03 2015

VALID 041200Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS MONDAY AFTERNOON AND EVENING
ACROSS PARTS OF NORTH CENTRAL/NORTHEAST KANSAS...SOUTH CENTRAL AND
SOUTHEAST NEBRASKA...SOUTHWEST IOWA AND NORTHWEST MISSOURI...

...THERE IS A SLGT RISK OF SVR TSTMS MONDAY AFTERNOON AND EVENING
ACROSS THE PECOS VALLEY AREA OF SOUTHWEST TEXAS AND EASTERN NEW
MEXICO...

...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLIGHT RISK
AREAS...FROM THE SOUTHERN HIGH PLAINS THROUGH THE CENTRAL
PLAINS...UPPER PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY AND
SOUTHERN PORTIONS OF THE GREAT LAKES REGION...

...SUMMARY...
A FEW SEVERE THUNDERSTORMS APPEAR POSSIBLE MONDAY AFTERNOON AND
EVENING ACROSS PARTS OF THE CENTRAL PLAINS INTO ADJACENT AREAS OF
THE MID MISSOURI VALLEY...AS WELL AS ACROSS THE PECOS VALLEY AREA OF
SOUTHWEST TEXAS AND EASTERN NEW MEXICO.

...SYNOPSIS...
MODELS CONTINUE TO SUGGEST AT LEAST SOME AMPLIFICATION WITHIN THE
STRONGEST BRANCH OF MID-LATITUDE WESTERLIES...ACROSS THE NORTH
CENTRAL AND NORTHEASTERN PACIFIC...DURING THIS PERIOD.  WITHIN THIS
REGIME...A VIGOROUS MID-LEVEL CLOSED LOW APPEARS LIKELY TO CONTINUE
GRADUALLY APPROACHING THE SOUTHERN BRITISH COLUMBIA AND PACIFIC
NORTHWEST COAST...BEFORE DIGGING INLAND MONDAY NIGHT.  DOWNSTREAM
SHORT WAVE RIDGING...BUILDING NEAR THE INTERNATIONAL BORDER
AREA...ACROSS AND EAST OF THE NORTHERN ROCKIES...APPEARS LIKELY TO
BE SUPPRESSED ON ITS NORTHEASTERN PERIPHERY BY A SERIES OF IMPULSES
DIGGING TO THE WEST AND SOUTH OF A MID-LEVEL CLOSED LOW NEAR HUDSON
BAY.  THIS INCLUDES ONE IMPULSE EMANATING FROM THE BELT OF
MID-LATITUDE WESTERLIES...WHICH IS FORECAST TO CONTINUE ACCELERATING
EAST SOUTHEAST OF JAMES BAY.

MEANWHILE...AT LOWER LATITUDES...A CLOSED LOW/TROUGH WITHIN A WEAKER
SOUTHERN BRANCH OF MID-LATITUDE WESTERLIES IS FORECAST TO CONTINUE
PROGRESSING INLAND ACROSS THE SOUTHWESTERN U.S. AND ADJACENT
NORTHERN MEXICO...AROUND THE NORTHWESTERN PERIPHERY OF BROAD
SUBTROPICAL RIDGING ACROSS MEXICO AND PORTIONS OF THE LOWER RIO
GRANDE VALLEY.  DOWNSTREAM...UPPER TROUGHING ACROSS THE CARIBBEAN
AND ADJACENT SOUTHEASTERN GULF OF MEXICO MAY AMPLIFY FURTHER.

IN LOWER LEVELS...THE COLD FRONT ASSOCIATED WITH THE QUEBEC IMPULSE
APPEARS LIKELY TO ADVANCE EAST SOUTHEAST OF THE LOWER GREAT LAKES
DURING THE DAY MONDAY...AND THROUGH MUCH OF THE NORTHEAST BY 12Z
TUESDAY.  ITS WESTERN FLANK...PERHAPS ENHANCED BY CONVECTIVE
OUTFLOW...IS GENERALLY EXPECTED TO STALL ACROSS PARTS OF THE CENTRAL
PLAINS INTO UPPER PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY.  WHILE
SURFACE RIDGING REMAINS PROMINENT ACROSS MUCH OF THE NORTHERN GULF
OF MEXICO AND GULF COAST STATES...A MORE SUBSTANTIVE RETURN FLOW
FROM THE GULF OF MEXICO MAY BEGIN TO DEVELOP ACROSS THE LOWER RIO
GRANDE VALLEY INTO THE HIGHER TERRAIN OF NORTHEAST MEXICO...AND
PERHAPS PORTIONS OF THE PECOS VALLEY.  MOISTENING ALONG THE
AFOREMENTIONED FRONT LIKELY WILL BE IN ASSOCIATION WITH THAT NOW
SLOWLY TAKING PLACE ACROSS THE SOUTHERN AND CENTRAL PLAINS INTO THE
MID MISSOURI VALLEY.  BUT SURFACE DEW POINT INCREASES INTO THE LOWER
60S MAY NOT BE OUT OF THE QUESTION WITHIN A CORRIDOR ALONG THE FRONT
BY MONDAY AFTERNOON.

...SRN PLAINS INTO CNTRL PLAINS/MID MS VALLEY/SRN GREAT LAKES...
A NARROW CORRIDOR OF STRONGER DAYTIME HEATING AND DESTABILIZATION IS
STILL EXPECTED TO BECOME FOCUSED JUST SOUTH OF THE SURFACE
FRONT...AND TO THE IMMEDIATE LEE OF THE HIGHER TERRAIN OF SOUTHWEST
TEXAS AND EASTERN NEW MEXICO BY LATE MONDAY AFTERNOON.  BENEATH
LINGERING STEEP MID-LEVEL LAPSE RATES ASSOCIATED WITH RESIDUAL
ELEVATED MIXED LAYER AIR...THIS ENVIRONMENT PROBABLY WILL BE
CONDUCIVE TO ISOLATED TO WIDELY SCATTERED STRONG/SEVERE STORM
DEVELOPMENT.

...NRN KS/SRN NEBRASKA/SWRN IA/NWRN MO...
CONFIDENCE IS INCREASING THAT THERE MAY BE A CORRIDOR OF MORE
SUBSTANTIVE SEVERE WEATHER POTENTIAL WITHIN A ZONE OF ENHANCED
CONVERGENCE ALONG THE FRONT ACROSS THE CENTRAL PLAINS INTO THE MID
MISSOURI VALLEY.  PARTICULARLY NEAR/EAST OF A WEAK SURFACE LOW
EXPECTED IN THE VICINITY OF HAYES/RUSSELL BY LATE
AFTERNOON...VEERING OF WINDS WITH HEIGHT...BENEATH MODEST /AROUND 30
KT/ SOUTHWESTERLY 500 MB FLOW MAY CONTRIBUTE TO AN ENVIRONMENT AT
LEAST MARGINALLY SUFFICIENT FOR SUPERCELLS.  THERMODYNAMIC PROFILES
PROBABLY WILL BE CHARACTERIZED BY STEEP MID-LEVEL LAPSE RATES AND
SIZABLE CAPE...WHICH SHOULD SUPPORT THE RISK FOR SEVERE HAIL.  A
COUPLE OF TORNADOES MAY NOT BE OUT OF THE QUESTION...BEFORE
CONVECTION CONSOLIDATES DURING THE EVENING...AIDED BY FORCING ON THE
NOSE OF A MODEST LOW-LEVEL JET.  THIS MAY BE ACCOMPANIED BY AT LEAST
A WINDOW OF OPPORTUNITY FOR STRONG SURFACE GUSTS BEFORE CONVECTION
WEAKENS.

...PECOS VALLEY...
ANOTHER CORRIDOR OF MORE SUBSTANTIVE SEVERE WEATHER POTENTIAL IS
EXPECTED TO DEVELOP IN ASSOCIATION WITH MOISTENING UPSLOPE FLOW
BENEATH STEEP MID-LEVEL LAPSE RATES ACROSS PARTS OF SOUTHWEST TEXAS
INTO EASTERN NEW MEXICO.  AIDED BY OROGRAPHIC FORCING... SCATTERED
DISCRETE STORM DEVELOPMENT SEEMS PROBABLE...IN THE PRESENCE OF
SUFFICIENT VERTICAL SHEAR /NEAR THE SUBTROPICAL JET/ FOR SUPERCELLS.

..KERR.. 05/03/2015



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