Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 
000
ACUS01 KWNS 111246
SWODY1
SPC AC 111244

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0644 AM CST WED DEC 11 2013

VALID 111300Z - 121200Z

...NO SVR TSTM AREAS FORECAST...

...ERN LAKE ONTARIO EWD TO THE TUG HILL PLATEAU OF NY...
INTENSE LAKE-EFFECT SNOW BANDING WILL BE MAINTAINED INVOF THE LONG
AXIS OF LAKE ONTARIO EWD ACROSS THE TUG HILL PLATEAU THROUGH MUCH OF
THE DAY -- PERHAPS ACCOMPANIED BY RE-CONSOLIDATION/EVOLUTION TO A
SOLITARY-BAND MODE THIS MORNING. THIS WILL OCCUR AS AMPLE COLD AIR
RESIDES OVER THE REGION IN THE MID LEVELS IN ASSOCIATION WITH A DEEP
POLAR VORTEX WHOSE PERIPHERY EXTENDS INTO THE GREAT LAKES REGION.
UNIDIRECTIONAL WLY FLOW SAMPLED BY THE 12Z BUF RAOB WILL CONTINUE TO
MAXIMIZE FETCH LENGTH OVER THE COMPARATIVELY WARMER LAKE WATERS TO
SUPPORT SUFFICIENTLY STEEP LOW-LEVEL LAPSE RATES/BUOYANCY FOR AN
ISOLATED THUNDERSTORM POTENTIAL WITH THE MOST INTENSE YET SHALLOW
CONVECTION THROUGH THE DAY. BY THIS EVENING...BOUNDARY-LAYER FLOW
WILL VEER FOLLOWING THE PASSAGE OF A REINFORCING COLD FRONT ARRIVING
FROM THE NW. THIS WILL DISRUPT ANY ANTECEDENT BANDED STRUCTURES AND
REDUCE THE FETCH LENGTH ACROSS THE LAKE...WHICH WILL BE COMMENSURATE
WITH A DECREASE IN THE THUNDER POTENTIAL AROUND/AFTER 00Z.

...SOUTH FLORIDA...
NWD TRANSPORT OF MID-LEVEL MOISTURE FROM THE WRN CARIBBEAN HAS BEEN
ASSOCIATED WITH 24-HOUR PW TENDENCIES AROUND POSITIVE 0.7 INCH PER
MFL AND KEY 12Z RAOBS. THIS WILL SUPPORT AN ENVIRONMENT SOMEWHAT
MORE FAVORABLE FOR DIURNAL CONVECTION THAN YESTERDAY...WITH SUCH
ACTIVITY FORCED BY ASCENT ACCOMPANYING A STALLED FRONT OVER THE
REGION AND SEA BREEZE BOUNDARIES. DESPITE THE PRESENCE OF AT LEAST
MARGINAL INSTABILITY THIS AFTERNOON...PROMINENT LAYERS OF MID-LEVEL
STATIC STABILITY WILL LIKELY PROVE TO BE DELETERIOUS FOR THE
SUSTENANCE OF DEEP UPDRAFTS. AN ISOLATED THUNDERSTORM CANNOT BE
ENTIRELY RULED OUT AROUND PEAK HEATING...THOUGH THE COVERAGE OF SUCH
ACTIVITY SHOULD BE TOO LIMITED FOR GENERAL-THUNDERSTORM DELINEATION.

..COHEN/MEAD.. 12/11/2013
USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.