Severe Storm Outlook Narrative (AC)
Issued by NWS

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173
ACUS01 KWNS 221635
SWODY1
SPC AC 221633

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1133 AM CDT FRI MAY 22 2015

VALID 221630Z - 231200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS ERN NM AND ADJACENT
PORTIONS OF WRN TX...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A SMALL PORTION OF NERN
CO...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE SRN HIGH PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE NERN QUARTER OF
CO...

...SUMMARY...
ISOLATED SEVERE STORMS ARE POSSIBLE LATE THIS AFTERNOON ACROSS
SOUTHWEST TEXAS...AND A SMALL PART OF NORTHEAST COLORADO.
THUNDERSTORM COVERAGE INCLUDING SOME SEVERE THREAT WILL INCREASE
THROUGH TONIGHT ACROSS EASTERN NEW MEXICO AND SOUTHWEST TO WEST
TEXAS.

...SYNOPSIS...
AS AN INITIAL MID-LEVEL VORT MAX NOW OVER THE CENTRAL HIGH PLAINS
CONTINUES NNEWD TOWARD/INTO THE NRN PLAINS...THE LARGER/MAIN WRN
TROUGH WILL CONTINUE A SLOW ADVANCE ACROSS THE WRN STATES.
DOWNSTREAM...RIDGING CENTERED INVOF THE MS VALLEY WILL AMPLIFY WITH
TIME...AS A SECOND TROUGH OVER THE NERN U.S./ERN CANADA GRADUALLY
DEPARTS.

AT THE SURFACE...BROAD LOW PRESSURE IS PROGGED ACROSS THE
INTERMOUNTAIN W...WITH A LEE LOW EXPECTED TO RESIDE OVER ERN CO
DURING THE AFTERNOON AND A LEE TROUGH EXTENDING SWD ACROSS ERN NM.
FARTHER E...HIGH PRESSURE WILL PREVAIL ACROSS THE CENTRAL
STATES...WHILE A SECONDARY/REINFORCING COLD FRONT MOVES SEWD ACROSS
THE NERN STATES THROUGH THE PERIOD.

...FAR W TX AND NWD ACROSS ERN NM...
DIURNAL HEATING OF A RELATIVELY MOIST AIRMASS BACKED WNWWD TO FAR W
TX/SERN NM WILL RESULT IN MODERATE DESTABILIZATION DURING THE
AFTERNOON -- LIKELY SUFFICIENT FOR ISOLATED THUNDERSTORM DEVELOPMENT
OVER THE HIGHER TERRAIN.  WITH LOW-LEVEL SELYS BENEATH INCREASING
WSWLYS AT MID LEVELS...DEGREE OF VEERING/SHEAR WILL FAVOR
ROTATING/SUPERCELL EVOLUTION...WITH LARGE HAIL AND DAMAGING WINDS
ALONG WITH POSSIBLY A TORNADO OR TWO.  DURING THE
EVENING/OVERNIGHT...INCREASING HEIGHT FALLS ACROSS THE SRN PLAINS
AHEAD OF THE ADVANCING WRN SYSTEM SUGGEST AN INCREASE IN CONVECTION
OVER ERN NM WILL BE POSSIBLE...SPREADING WITH TIME INTO THE TX
PANHANDLE AND S PLAINS REGION.  THOUGH INSTABILITY WILL LIKELY BE
LIMITED...INCREASINGLY FAVORABLE SHEAR AHEAD OF THE ADVANCING TROUGH
SUGGESTS A FEW STRONGER STORMS WILL BE CAPABLE OF PRODUCING HAIL
AND/OR DAMAGING WINDS.

...NERN CO...
CLEARING IS OCCURRING FROM S-N ACROSS CO ATTM...AS THE VORT MAX
SHIFTS NWD/AWAY FROM THE AREA.  WHILE SHORT-WAVE RIDGING SHOULD
SUPPRESS CONVECTION IN THE NEAR TERM...HEATING/DESTABILIZATION
THROUGH THE AFTERNOON MAY SUPPORT ISOLATED STORM DEVELOPMENT --
AIDED BY SELY UPSLOPE FLOW JUST N OF THE SURFACE LOW -- AS
LARGER-SCALE HEIGHT FALLS OCCUR AHEAD OF THE MAIN UPPER SYSTEM.
WITH THE LOW-LEVEL SELYS ALSO CONTRIBUTING TO SUBSTANTIAL VEERING
WITH HEIGHT AS FLOW BECOMES WNWLY AT MID LEVELS...SHEAR SUPPORTIVE
OF ROTATING STORMS -- AND ATTENDANT RISKS FOR HAIL AND DAMAGING
WINDS ALONG WITH A TORNADO OR TWO REMAIN EVIDENT INTO THIS EVENING.

..GOSS/ROGERS.. 05/22/2015




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