DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0805 AM CDT MON APR 19 2004
VALID 191300Z - 201200Z
THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 35 SE
CDS 25 E PVW 25 NNW PVW 35 E DHT 60 S GLD 15 NE GLD 15 SE MCK 40 SSW
EAR 40 S HSI 25 ENE SLN 25 NE CNU 30 WNW JLN 40 NE TUL 40 NNE OKC 35
SE CDS.
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 75 SSW GDP 25 N CNM
45 W CVS 40 W TCC 20 NNE LVS 35 NNE 4SL 15 WNW CEZ 50 W 4HV 50 E ELY
45 WNW ENV 35 E OWY 30 SW BOI 20 S BKE 45 WNW PDT 50 SW 63S 45 ENE
63S 50 NE MSO 15 WSW GTF 55 NE LWT 50 NNW GGW ...CONT... 70 NE MOT
30 SE BIS 45 NE PIR 30 SW MHE 50 NE OMA 40 NE IRK 30 WSW SPI 30 NW
HUF 15 ENE LAF 10 NNE SBN 25 NW TVC 40 WNW ANJ ...CONT... 35 NNW CAR
20 ENE EEN 25 NE ABE 40 W EKN 15 SW JKL 50 N CSV 30 SW BNA 45 N TUP
55 W UOX 40 N GGG 15 W ACT 50 E JCT 65 W COT.
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE TX/OK PNHDLS INTO
NWRN-NRN OK AND NWD TO MUCH OF KS/FAR SOUTH CENTRAL NEB...
...SYNOPSIS...
PROGRESSIVE UPPER LEVEL FLOW WILL CONTINUE OVER THE U.S. TODAY AS
ONE SHORT WAVE TROUGH TRACKS FROM THE UPPER GREAT LAKES REGION EWD
TO NEW ENGLAND. MEANWHILE...UPSTREAM TROUGH...CURRENTLY EXTENDING
FROM OREGON TO SRN CA...WILL MOVE EWD REACHING THE NRN HIGH PLAINS
SSEWD TO SRN PLAINS BY 12Z TUESDAY...AS PACIFIC TROUGH MOVES INTO
THE PAC NW.
AT THE SURFACE...COLD FRONT ASSOCIATED WITH GREAT LAKES TROUGH WILL
MOVE ESEWD ACROSS THE NERN STATES AND OH VALLEY TODAY. THE WRN
PORTION OF THIS FRONT...CURRENTLY EXTENDING FROM CENTRAL MO SWWD
THROUGH NWRN OK TO THE TX PANHANDLE. THIS PORTION OF THE BOUNDARY
MAY SAG A LITTLE FURTHER S ACROSS OK AND NWRN TX THIS MORNING... BUT
SHOULD RETREAT NWD AS A WARM FRONT TO NRN OK BY 00Z AND INTO KS
OVERNIGHT IN RESPONSE TO THE CA TROUGH.
...TX/OK PNHDLS/NWRN-NRN OK NWD ACROSS MUCH OF KS/FAR SCNTRL NEB...
A LEAD SHORT WAVE TROUGH...EVIDENT ON WV IMAGERY TO THE SOUTH OF ELP
AT 12Z...WILL MOVE NEWD ACROSS OK BY LATE THIS AFTERNOON IN ADVANCE
OF UPSTREAM CA TROUGH. WV IMAGERY SHOWS A PLUME OF MID-UPPER LEVEL
MOISTURE/CLOUDINESS EXTENDING FROM NRN MEXICO NEWD ACROSS WRN/NRN
TX/OK TO THE MID MS VALLEY AND LOWER GREAT LAKES. THE WRN EDGE OF
THIS CLOUD SHIELD OVER WRN TX/OK IS EXPECTED TO MOVE NWD AS SHORT
WAVE RIDGING DEVELOPS OVER THE CENTRAL/NRN PLAINS IN ADVANCE OF
UPSTREAM LONG TROUGH. INCREASING LARGE SCALE ASCENT AHEAD OF THE
LEAD SHORT WAVE TROUGH SHOULD PROVE SUFFICIENT TO SUPPORT ELEVATED
CONVECTION WITHIN MID/UPPER LEVEL MOISTURE PLUME ACROSS WRN TX INTO
OK BY LATE MORNING INTO THE AFTERNOON. ALTHOUGH THE AIR MASS
BENEATH THIS MID-LEVEL CONVECTION WILL BE MOIST WITH SURFACE
DEWPOINTS IN THE LOWER 60S...WARM TEMPERATURES AT 700 MB PER 09Z RUC
SOUNDINGS WILL LIKELY INHIBIT SURFACE BASED STORMS FROM DEVELOPING
THIS AFTERNOON. HOWEVER...IF STORMS CAN BECOME ROOTED IN THE
BOUNDARY LAYER ALONG THE DRY LINE IN THE TX PANHANDLE AND/OR ALONG
WARM FRONT INTO NWRN OK...SUFFICIENT DEEP LAYER...STEEP LAPSE
RATES...AND MODERATE INSTABILITY WOULD SUPPORT DISCRETE SUPERCELLS
WITH LARGE HAIL AND DAMAGING WINDS THE PRIMARY THREATS.
GREATER SEVERE THREAT SHOULD...HOWEVER...DEVELOP THIS EVENING AND
OVERNIGHT AS A DOUBLE BRANCH LLJ STRENGTHENS ACROSS WRN TX TO WRN KS
AND THE SECOND BRANCH EXTENDS FROM CENTRAL TX TO ERN OK IN RESPONSE
TO HEIGHT FALLS WITH THE APPROACH OF THE UPSTREAM TROUGH.
INCREASING LARGE SCALE ASCENT AND COOLING MID-LEVEL TEMPERATURES
WITH THIS FEATURE WILL LIKELY SUPPORT ELEVATED MULTI-CELLS AND
ISOLATED SUPERCELLS NWD INTO KS...AND POTENTIALLY CENTRAL NEB.
ELEVATED CAPE AOA 1000 J/KG WILL FAVOR HAIL AS THE PRIMARY THREAT
WITH EVENING/OVERNIGHT ACTIVITY.
...PORTIONS ERN OH/NWRN PA/NY...
SURFACE HEATING AHEAD OF COLD FRONT WILL SUPPORT THE DEVELOPMENT OF
MARGINAL INSTABILITY BY EARLY AFTERNOON FROM NERN-ERN OH INTO NY.
CONVECTION SHOULD DEVELOP AS THE COLD FRONT SAGS SWD ACROSS THIS
REGION WITH DEEP LAYER SHEAR AND MARGINAL INSTABILITY SUPPORTING AN
ISOLATED SEVERE THREAT.
...ERN WY/SWRN SD...
THUNDERSTORMS SHOULD DEVELOP ACROSS THE HIGHER TERRAIN OF SERN/ERN
WY INTO SWRN SD BY LATE THIS AFTERNOON...AS SUFFICIENT SURFACE
HEATING WEAKENS THE CAP. MARGINAL LOW-LEVEL MOISTURE WILL LIMIT THE
SEVERE POTENTIAL...BUT HIGH BASED NATURE OF THIS ACTIVITY AND
STEEPENING LAPSE RATES SHOULD SUPPORT AT BEST AN ISOLATED HAIL
AND/OR STRONG WIND GUST.
..PETERS/GUYER.. 04/19/2004
Looks like the LLJ structure will kick up again overnight and increase chances of severe weather across much of the Mid West and the Southern Plains. Since WAA will be taking place with MDT instability.....looks like supercells will be a good bet. Expecially if winds back enough in the region. Hodographs have a nice big loop this morning...so I will be watching the situation throughout the day.
