Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
SPC AC 040530
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 AM CDT SAT JUN 04 2016
VALID 041200Z - 051200Z
...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING
ACROSS MUCH OF THE OHIO VALLEY AND NORTHERN AND CENTRAL
APPALACIANS...
...THERE IS A MRGL RISK OF SVR TSTMS ACROSS MUCH OF THE REMAINDER OF
THE OHIO VALLEY AND APPALACHIANS...INTO PARTS OF THE NORTHERN MID
ATLANTIC COAST STATES...
...SUMMARY...
THUNDERSTORMS MAY IMPACT MUCH OF THE OHIO VALLEY AND APPALACHIANS
REGION TODAY...ACCOMPANIED BY THE RISK FOR POTENTIALLY DAMAGING WIND
GUSTS.
...SYNOPSIS...
MODELS INDICATE SOME FURTHER AMPLIFICATION OF LARGE-SCALE RIDGING
NOW BUILDING ACROSS MUCH OF WESTERN NORTH AMERICA DURING THIS
PERIOD...MAINLY ALONG THE CANADIAN ROCKIES...WITH SOME EXPANSION
EAST OF THE ROCKIES...INTO PARTS OF THE NORTHERN AND CENTRAL PLAINS.
THIS LATTER DEVELOPMENT IS EXPECTED IN THE WAKE OF UPPER TROUGHING
WITHIN THE MID-LATITUDE WESTERLIES...WHICH IS FORECAST TO SLOWLY
PROGRESS EASTWARD INTO THE MID/UPPER MISSISSIPPI VALLEY. SOME
SHARPENING OF THIS TROUGHING IS POSSIBLE SOUTHWARD THROUGH THE
MISSISSIPPI VALLEY...BEFORE DOWNSTREAM SUBTROPICAL RIDGING ACROSS
THE SOUTHEAST AND MID ATLANTIC REGION BEGINS TO WEAKEN. FOR A
PERIOD...THIS TROUGHING MAY ALSO COME INCREASINGLY IN PHASE WITH
REMNANT SOUTHERN STREAM UPPER TROUGHING ACROSS EASTERN TEXAS INTO
NORTHEAST MEXICO...ALONG WHICH AN ELONGATED CYCLONIC CIRCULATION MAY
CONTINUE DEVELOPING SOUTHWARD ACROSS THE LOWER RIO GRANDE VALLEY.
AT THE SAME TIME...WITHIN THE BROADER SCALE UPSTREAM ANTICYCLONIC
UPPER FLOW...AN IMPULSE EMERGING FROM THE SUBTROPICAL EASTERN
PACIFIC IS FORECAST TO PROGRESS INLAND INTO NORTHERN AND CENTRAL
CALIFORNIA.
IN ASSOCIATION WITH THESE DEVELOPMENTS...DESTABILIZATION MAY LEAD TO
SCATTERED LATE AFTERNOON AND EVENING THUNDERSTORM ACTIVITY ACROSS
PARTS OF THE SOUTHERN CASCADES ...SHASTAS AND SISKIYOUS INTO THE
NORTHERN SIERRA NEVADA MOUNTAINS...AS WELL AS ACROSS THE MOUNTAINS
OF CENTRAL IDAHO INTO WESTERN WYOMING...AND ACROSS THE SOUTHERN
ROCKIES. EAST OF THE ROCKIES...STEEP LOWER/MID TROPOSPHERIC LAPSE
RATES SHOULD MOSTLY BE CONFINED TO THE PLAINS...WHERE CONSIDERABLE
FURTHER DRYING IS FORECAST ON NORTHERLY TO NORTHWESTERLY DEEP LAYER
FLOW. MODELS INDICATE SEASONABLY HIGH MOISTURE CONTENT AIR WILL
BECOME INCREASINGLY CONFINED TO THE WESTERN GULF COAST REGION...AND
AREAS EAST OF THE MISSISSIPPI VALLEY...WHILE ADVECTING NORTHWARD
ACROSS THE LOWER GREAT LAKES REGION AND HUDSON/CHAMPLAIN
VALLEY...AHEAD OF A BROAD DEEPENING SURFACE LOW OVER THE UPPER GREAT
LAKES. WITHIN THIS MOIST REGIME... CONSIDERABLE THUNDERSTORM
APPEARS LIKELY...WITH COVERAGE BECOMING MAXIMIZED IN PEAK LATE
AFTERNOON/EVENING BOUNDARY LAYER INSTABILITY DRIVEN LARGELY BY
INSOLATION.
...OHIO VALLEY INTO APPALACHIANS AND PARTS OF THE NORTHERN MID
ATLANTIC STATES...
ALTHOUGH THERE MAY BE CONSIDERABLE EARLY DAY CLOUD
COVER...PARTICULARLY IN MID/UPPER LEVELS...MUCH OF THE REGION IS
EXPECTED TO BE PRECIPITATION-FREE...ALLOWING FOR AT LEAST MODEST
BOUNDARY LAYER DESTABILIZATION /CAPE ON THE ORDER OF 1000+ J PER KG/
TO TAKE PLACE WITH INSOLATION. THIS PROBABLY WILL LEAD TO
INCREASING THUNDERSTORM DEVELOPMENT DURING THE 18-21Z TIME
FRAME...WHICH SHOULD CONTINUE TO GRADUALLY INCREASE IN
COVERAGE/INTENSITY THROUGH THE REMAINDER OF THE AFTERNOON.
MODELS INDICATE THAT STORM DEVELOPMENT WILL COINCIDE WITH
STRENGTHENING OF SOUTHWESTERLY MID-LEVEL FLOW /TO 30-40+ KT IN THE
700-500 MB LAYER/...BETWEEN THE APPROACHING UPPER TROUGH AND THE
LINGERING SUBTROPICAL RIDGE. THIS MAY CONTRIBUTE TO MARGINALLY
SUFFICIENT VERTICAL SHEAR FOR THE EVOLUTION OF ORGANIZED STORM
CLUSTERS WITH AT LEAST MODEST STORM MOTIONS. AIDED BY HEAVY
PRECIPITATION LOADING AND DOWNWARD MOMENTUM TRANSPORT...STRONGER
ACTIVITY PROBABLY WILL BE ACCOMPANIED BY OCCASIONAL POTENTIALLY
DAMAGING WIND GUSTS THROUGH AT LEAST EARLY THIS EVENING.
..KERR/LEITMAN.. 06/04/2016
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
| 
)
