DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 201606
SWODY1
SPC AC 201604

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1104 AM CDT SAT APR 20 2013

VALID 201630Z - 211200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

A BROAD...CYCLONIC FLOW REGIME WILL BE MAINTAINED ACROSS THE LOWER
48 THROUGH THE D1 PERIOD. WITHIN THIS PATTERN...A 100+ KT MIDLEVEL
JET STREAK AND ASSOCIATED VORTICITY RIBBON OVER THE LOWER GREAT
LAKES INTO CNTRL QUEBEC WILL MOVE POLEWARD INTO THE CANADIAN
MARITIMES IN ADVANCE OF MULTI-STREAM VORTICITY MAXIMA PROGRESSING
FROM THE ROCKIES INTO THE CNTRL CONUS. IN THE LOW LEVELS...THE
TRAILING SEGMENT OF A COLD FRONT ADVANCING EWD THROUGH THE WRN
ATLANTIC WILL SETTLE SEWD THROUGH THE REMAINDER OF THE FL PENINSULA.
ELSEWHERE...A WARM FRONT WILL MOVE NEWD THROUGH THE NRN PLAINS AND
MID/LOWER-MO VALLEY...AHEAD OF A COLD FRONT SHIFTING SEWD THROUGH
THE NRN HIGH PLAINS.

...FL...

WIDELY SCATTERED...ELEVATED TSTMS WILL BE POSSIBLE WITHIN
POST-FRONTAL SURFACE ENVIRONMENT...AND FOCUSED ALONG 850-MB FRONT AS
DEEP-LAYER ASCENT IS ENHANCED BY A LOW-AMPLITUDE PERTURBATION
CURRENTLY OVER THE NERN G.O.M. SURFACE-BASED STORMS WILL ALSO BE
POSSIBLE THIS AFTERNOON ALONG/AHEAD OF THE SURFACE COLD
FRONT...ESPECIALLY WHERE IT INTERSECTS THE DEVELOPING EAST COAST SEA
BREEZE. THE PRESENCE OF A MOIST AND MODERATELY UNSTABLE AIR MASS
WILL PROMOTE VIGOROUS UP/DOWNDRAFTS WITH A RISK FOR LOCALLY STRONG
WIND GUSTS. HOWEVER...GENERALLY WEAK VERTICAL SHEAR WILL PRECLUDE
ORGANIZED SEVERE WEATHER POTENTIAL.

...NRN/CNTRL ROCKIES INTO ADJACENT HIGH PLAINS...

FORCING ASSOCIATED WITH THE ABOVE-MENTIONED VORTICITY MAXIMA COUPLED
WITH A DRY...BUT STEEP LAPSE-RATE ENVIRONMENT WILL FOSTER WIDELY
SCATTERED TSTMS THIS AFTERNOON AND EVENING. EVAPORATIVE COOLING
WITHIN INVERTED-V SUB-CLOUD LAYERS MAY PROMOTE GUSTY WINDS...THOUGH
NO SEVERE WEATHER IS ANTICIPATED.

..MEAD/DEAN.. 04/20/2013

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