We’re keeping an eye on the severe weather potential later this week/weekend as a fairly vigorous area of low pressure looks to develop in the Western U.S.. The image below shows the current area of energy/interest just west of the Pacific Northwest.
Increasing Instability
As the storm system develops over the next several days, it appears weather conditions on the eastern side of the storm will begin to become increasingly more unstable. The images below show the available energy (CAPE) for Friday and Saturday afternoon. Note that the more intense oranges and reds, which indicates a fairly substantial amount of energy available for storms to develop and feed from.
CAPE Friday 7pm CT
CAPE Saturday 1pm CT
Severe Threat Friday
…SUMMARY…
SEVERE STORMS ARE EXPECTED TO DEVELOP FRIDAY AFTERNOON AND EVENING
OVER THE CENTRAL PLAINS WITH MORE ISOLATED DEVELOPMENT POSSIBLE
FARTHER SOUTH ACROSS WESTERN PORTIONS OF THE SOUTHERN PLAINS.
…SYNOPSIS…
MODEL CONSENSUS IS THAT A LEAD SHORTWAVE TROUGH WILL EJECT NEWD
THROUGH THE CNTRL PLAINS FRIDAY IN ADVANCE OF A SYNOPTIC TROUGH THAT
WILL MOVE SLOWLY EWD THROUGH THE GREAT BASIN AND CNTRL/SRN ROCKIES.
AT THE SFC A LEE LOW WILL PERSIST OVER ERN CO AND SHIFT SLOWLY EWD
DURING THE DAY WHILE A DRYLINE SHARPENS FROM WRN KS AND WILL EXTEND
SWD THROUGH WRN TX. A WARM FRONT WILL EXTEND EWD FROM THE LOW
THROUGH SRN NEB AND SRN IA EARLY FRIDAY AND LIFT SLOWLY NWD DURING
THE DAY.
…NRN KS THROUGH NEB AND SRN SD…
AREAS OF ELEVATED CONVECTION MAY BE ONGOING OVER NEB EARLY FRIDAY
WITHIN ZONE OF ISENTROPIC ASCENT NORTH OF WARM FRONT. THIS ACTIVITY
SHOULD SHIFT NWD WITH ADVANCING WARM FRONT DURING THE COURSE OF THE
DAY. ATMOSPHERE SHOULD DESTABILIZE EAST OF SHARPENING DRYLINE AND
NEAR/SOUTH OF WARM FRONT WHERE LOW 60 F DEWPOINTS WILL ADVECT NWD
BENEATH PLUME OF STEEPER LAPSE RATES AND WHERE DIABATIC WARMING OF
THE SFC LAYER IS MOST LIKELY TO OCCUR. MLCAPE FROM 1500-2500 J/KG
APPEARS LIKELY FROM SRN NEB INTO NRN KS WARM SECTOR BY AFTERNOON.
STORMS ARE EXPECTED TO REDEVELOP ALONG ARCING DRYLINE AS IT MIXES
NEWD AS WELL AS IN VICINITY OF WARM FRONT FROM SRN/CNTRL NEB INTO
NRN KS AND SPREAD NEWD DURING THE DAY. IF SUFFICIENT INSTABILITY CAN
BE REALIZED NEAR THE WARM FRONT…IMPRESSIVE 0-1 KM HODOGRAPHS WILL
SUPPORT LOW-LEVEL MESOCYCLONES AND A FEW TORNADOES. OTHERWISE
SUPERCELLS WITH LARGE HAIL AND DAMAGING WIND WILL BE LIKELY FROM
FRIDAY AFTERNOON INTO EARLY EVENING.
…WRN TX THROUGH WRN OK AND SRN KS…
ATMOSPHERE EAST OF THE DRYLINE WILL BECOME MODERATELY TO STRONGLY
UNSTABLE WHERE MID-UPPER 60S DEWPOINTS WILL RESIDE IN WARM SECTOR.
PRIMARY UNCERTAINTY IS EXTENT OF THUNDERSTORM INITIATION GIVEN
LIKELIHOOD OF AT LEAST A MODEST CAP AND TENDENCY FOR DEEPER FORCING
WITH LEAD WAVE TO REMAIN WELL NORTH OF THIS REGION.
NEVERTHELESS…AT LEAST MODEST DRYLINE CONVERGENCE SHOULD PROMOTE
THE DEVELOPMENT OF AT LEAST ISOLATED STORMS WITHIN AN ENVIRONMENT
SUPPORTIVE OF SUPERCELLS. OVERNIGHT ADDITIONAL STORMS ARE EXPECTED
TO DEVELOP AND SPREAD INTO WRN OK AS PACIFIC FRONT MERGERS WITH
RETREATING DRYLINE.
Severe Threat Saturday
SATURDAY /DAY 4/ A MOIST WARM SECTOR WILL RESIDE EAST OF A PACIFIC
FRONT THAT WILL ACCOMPANY AN UPPER TROUGH THROUGH THE PLAINS. THE
PRIMARY COMPLICATING FACTOR THIS FORECAST WILL BE THE POTENTIAL FOR
EARLY CONVECTION OVER PORTIONS OF THE WARM SECTOR WITH GREATEST
COVERAGE CURRENTLY FORECAST FROM PARTS OF NRN TX INTO PARTS OF OK
AND KS. GIVEN THE MOIST BOUNDARY LAYER IN PLACE…POTENTIAL WILL
EXIST FOR ATMOSPHERE TO BECOME AT LEAST MODERATELY UNSTABLE DURING
THE AFTERNOON. STORMS WILL LIKELY REDEVELOP ALONG AND AHEAD OF THE
FRONT WITHIN DIFLUENT UPPER FLOW REGIME. DEEP-LAYER WIND PROFILES
WILL REMAIN LARGELY MERIDIONAL BUT WILL STRENGTHEN WITH APPROACH OF
THE UPPER TROUGH AND BECOME SUPPORTIVE OF ORGANIZED SEVERE STORMS.
Severe Threat Sunday
SUNDAY /DAY 5/ SEVERE THREAT WILL SHIFT INTO THE UPPER MS VALLEY AND
GREAT LAKES REGION IN ASSOCIATION WITH THE PROGRESSIVE UPPER TROUGH
AND ATTENDANT STRONG DEEP-LAYER WIND PROFILES. AS IN DAY 4…EARLY
CONVECTION WILL ALSO COMPLICATE FORECAST AND INCREASE UNCERTAINTY
REGARDING WHERE GREATEST SEVERE POTENTIAL WILL EVOLVE.
Heavy Rainfall Potential
According to NOAA’s HPC, the 5 day rainfall forecast for parts of the Central U.S. look pretty wet again. Note that some areas near Dallas/Ft. Worth, TX could potentially see as much as 2″ to nearly 5″ of rain through early next week. Kepe in mind that some of these areas have already seen 6″ to nearly 10″ of rain already over the past 7 days. Flooding will likely be an ongoing issue for some of those locations.
Thanks for checking in and have a great rest of your week. Don’t forget to follow me on Twitter @TNelsonWX
