Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 281716
SWODY2
SPC AC 281715

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1115 AM CST WED JAN 28 2015

VALID 291200Z - 301200Z

...NO TSTM AREAS FORECAST...

...SUMMARY...
THE RISK FOR THUNDERSTORMS APPEARS NEGLIGIBLE ACROSS THE U.S.
THURSDAY THROUGH THURSDAY NIGHT.

...SYNOPSIS...
MUCH AS MODELS CONTINUE TO SUGGEST...AT LEAST SOME AMPLIFICATION
WITHIN THE NORTHERN BRANCH OF SPLIT WESTERLIES EMERGING FROM THE
PACIFIC APPEARS UNDERWAY...WITH MID/UPPER RIDGING NOW BUILDING ALONG
THE BRITISH AND PACIFIC NORTHWEST COAST.  AS THE LARGE-SCALE
ANTICYCLONIC REGIME EXPANDS EAST OF THE CANADIAN/NORTHERN U.S.
ROCKIES LATER TODAY THROUGH THURSDAY...DOWNSTREAM UPPER TROUGH
AMPLIFICATION IS FORECAST...FROM THE UPPER MIDWEST AND LOWER OHIO
VALLEY INTO THE ATLANTIC SEABOARD BY 12Z FRIDAY.

THIS LATTER DEVELOPMENT APPEARS LIKELY TO INCLUDE THE CONSOLIDATION
OF SEVERAL SHORT WAVE IMPULSES...INCLUDING ONE OF SUBTROPICAL
TROPICAL EASTERN PACIFIC ORIGIN...WHICH IS EXPECTED TO APPROACH THE
LOWER OHIO VALLEY BY 12Z THURSDAY.  AS THIS FEATURE BECOMES ABSORBED
WITHIN SHARPENING LARGER-SCALE CYCLONIC FLOW... VARIABILITY AMONG
THE MODELS INCREASES CONCERNING ITS SUBSEQUENT EVOLUTION...BUT IT
SEEMS LIKELY TO CONTINUE TO CONTRIBUTE TO SUBSTANTIVE FORCING FOR
UPWARD VERTICAL MOTION ACROSS THE LOWER OHIO VALLEY INTO THE
APPALACHIANS DURING THE DAY THURSDAY.  PRECEDED BY MOISTENING ON
SOUTH TO SOUTHWESTERLY LOWER/MID TROPOSPHERIC FLOW...IT DOES APPEAR
THAT STEEPENING OF MID-LEVEL LAPSE RATES MAY BE SUFFICIENT TO
SUPPORT THE DEVELOPMENT OF ONE OR MORE BANDS OF WEAK CONVECTION.
BUT THERMODYNAMIC PROFILES...IN GENERAL...STILL DO NOT APPEAR
PARTICULARLY CONDUCIVE TO AN APPRECIABLE RISK FOR THUNDERSTORM
ACTIVITY.

MEANWHILE...CONSIDERABLE MID-LEVEL MOISTENING IS EXPECTED THROUGH
THE PERIOD ON SOUTHERLY FLOW ACROSS NORTHERN MEXICO INTO THE FOUR
CORNERS REGION...AHEAD OF LARGE-SCALE UPPER TROUGHING WITHIN THE
SOUTHERN BRANCH OF THE SPLIT WESTERLIES.  COUPLED WITH WEAK FORCING
FOR ASCENT...THIS PROBABLY WILL LEAD TO INCREASING
PRECIPITATION...THOUGH MOSTLY FROM MID/HIGH-LEVEL CONVECTION.  WITH
THERMODYNAMIC PROFILES TENDING TO SATURATE FROM TOP DOWN IN
ASSOCIATION WITH EVAPORATING PRECIPITATION...AND THE MID-LEVEL COLD
CORE OF THE UPPER TROUGH FORECAST TO REMAIN WEST OF THE
CALIFORNIA/BAJA COAST...THE RISK FOR DESTABILIZATION SUPPORTIVE OF
THUNDERSTORMS APPEARS NEGLIGIBLE THROUGH 12Z FRIDAY.

..KERR.. 01/28/2015



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