Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 051923
SWODY1
SPC AC 051921

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0121 PM CST FRI FEB 05 2016

VALID 052000Z - 061200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
ISOLATED THUNDERSTORMS ARE POSSIBLE OVER THE PACIFIC NORTHWEST
COAST...MAINLY TONIGHT.

...DISCUSSION...

NO CHANGES TO 1630Z NECESSARY.

..DARROW.. 02/05/2016

.PREV DISCUSSION... /ISSUED 1021 AM CST FRI FEB 05 2016/

...SYNOPSIS...
IN THE WAKE OF A COLD FRONT...WHICH HAS ADVANCED EAST OF THE
ATLANTIC SEABOARD AND THROUGH MUCH OF THE GULF OF MEXICO...GENERALLY
DRY AND/OR STABLE CONDITIONS ARE PREVALENT ACROSS MUCH OF THE
NATION.  LITTLE CHANGE IS EXPECTED THROUGH THE REMAINDER OF TODAY
AND TONIGHT ACROSS MOST AREAS.

...PACIFIC NORTHWEST...
ONE EXCEPTION MAY BE ACROSS PARTS OF THE PACIFIC NORTHWEST COAST
THIS EVENING INTO THE OVERNIGHT HOURS...AS A VIGOROUS SHORT WAVE
TROUGH MIGRATES INLAND OFF THE EASTERN PACIFIC...AROUND THE CREST OF
LARGER-SCALE MID/UPPER RIDGING.  FORECAST SOUNDINGS SUGGEST THAT
STEEPENING LAPSE RATES ASSOCIATED WITH STRONG MID-LEVEL COOLING
/INCLUDING TO AROUND OR BELOW -30C AT 500 MB/ MAY CONTRIBUTE TO
THERMODYNAMIC PROFILES CONDUCIVE TO THUNDERSTORM DEVELOPMENT.  THIS
IS EXPECTED TO BE MOSTLY CONFINED TO THE LOWER ELEVATIONS WEST OF
THE NORTHERN CASCADES DURING THE 06/03-09Z TIME FRAME.  IT APPEARS
THAT THIS WILL COINCIDE WITH SUBSTANTIAL STRENGTHENING OF LOWER/MID
TROPOSPHERIC WIND FIELDS ACCOMPANYING A 100+ KT 500 MB JET STREAK.
WHILE SOME CONVECTIVE ENHANCEMENT OF SURFACE GUSTS /ASSOCIATED WITH
DOWNWARD MOMENTUM TRANSFER/ IS POSSIBLE...THE RISK FOR VIGOROUS
THUNDERSTORM DEVELOPMENT STILL APPEARS TOO NEGLIGIBLE FOR EVEN 5
PERCENT SEVERE PROBABILITIES.

...TEXAS...
STRONG MID-LEVEL COOLING /INCLUDING TO AROUND -30C AT 500 MB/...
ACCOMPANYING A VIGOROUS SHORT WAVE TROUGH DIGGING TO THE SOUTHEAST
OF THE CENTRAL AND SOUTHERN ROCKIES...MAY CONTRIBUTE TO WEAK
LOWER/MID TROPOSPHERIC DESTABILIZATION ACROSS PARTS OF NORTH CENTRAL
THROUGH SOUTHEAST TEXAS LATE THIS EVENING INTO THE OVERNIGHT HOURS.
THIS PROBABLY WILL BE SUFFICIENT TO SUPPORT AT LEAST SOME CONVECTIVE
DEVELOPMENT.  BUT...WITH LOW-LEVEL MOISTURE LIMITED DUE TO A LACK OF
A SUBSTANTIVE RETURN FLOW OFF THE GULF OF MEXICO...IT REMAINS
UNCLEAR WHETHER THERMODYNAMIC PROFILES WILL BECOME CONDUCIVE TO
CHARGE SEPARATION...AND AN APPRECIABLE RISK FOR LIGHTNING.  AT THIS
TIME...THE RISK FOR THUNDERSTORMS STILL SEEMS TO REMAIN BELOW THE
MINIMUM 10 PERCENT THRESHOLD FOR A CATEGORICAL THUNDERSTORM
FORECAST.

$$


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