Could be a pretty rare and exciting day Tomorrow, but things need to go nearly perfect
SPC AC 051730
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT SAT JUN 05 2010
VALID 061200Z - 071200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SRN NEW
ENGLAND...NJ...ERN PA AND THE MID-ATLANTIC...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL
APPALACHIAN MTNS...
...NEW ENGLAND/NJ/ERN PA/MID-ATLANTIC/CNTRL APPALACHIANS...
A RELATIVELY LOW-AMPLITUDE UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS
THE ERN GREAT LAKES AND UPPER OH VALLEY SUNDAY. AHEAD OF AND SOUTH
OF THE UPPER-LEVEL TROUGH...A WELL-DEVELOPED LINE OF THUNDERSTORMS
SHOULD BE ONGOING SUNDAY MORNING FROM WRN NY SWWD ACROSS OH INTO SRN
IND WITH THE LINE MOVING ESEWD INTO THE CNTRL AND NRN APPALACHIAN
MTNS BY MIDDAY. A MARGINAL SEVERE THREAT SHOULD EXIST WITH THIS LINE
DURING THE MORNING WITH THE SEVERE THREAT GRADUALLY INCREASING AS
SFC TEMPS WARM DURING THE DAY. THE GREATEST THREAT FOR SEVERE SHOULD
BE CO-LOCATED WITH THE EXIT REGION OF A 75 TO 90 KT MID-LEVEL JET
MOVING ACROSS SRN NEW ENGLAND SUNDAY AFTERNOON. ETA-KF FORECAST
SOUNDINGS AT THAT TIME IN MA AND CT SHOW MLCAPE OF 1000 TO 1500 J/KG
AND 0-6 KM SHEAR IN THE 50 TO 60 KT RANGE WHICH SHOULD SUPPORT
SUPERCELL DEVELOPMENT. 0-3 KM STORM RELATIVELY HELICITIES OF 350 TO
400 M2/S2 COULD BE FAVORABLE FOR TORNADOES BUT THIS THREAT SHOULD BE
DEPENDENT UPON STORM MODE. IF THE PREDOMINANT STORM TYPE IS
LINEAR...THEN WIND DAMAGE COULD BE THE PRIMARY THREAT. WITH 850 MB
FLOW AT 50 TO 60 KT...ANY FAST-MOVING LINES COULD PRODUCE VERY
STRONG WIND GUSTS. THIS POTENTIAL FOR VERY STRONG WIND GUSTS SHOULD
EXTEND SWWD INTO NEW JERSEY ALONG THE SRN EDGE OF THE MID-LEVEL JET.
FURTHER WSW INTO THE CNTRL APPALACHIAN MTNS...A SEVERE THREAT SHOULD
ALSO EXIST SUNDAY AFTERNOON WHERE THE MODELS ARE FORECASTING
MODERATE INSTABILITY. ETA-KF FORECAST SOUNDINGS IN ERN KY SUNDAY AT
21Z SHOW 35 TO 45 KT OF 0-6 KM SHEAR WITH UNIDIRECTIONAL SHEAR
PROFILES. THIS SHOULD BE FAVORABLE FOR BOWING LINE-SEGMENTS WITH A
THREAT FOR DAMAGING WIND GUSTS ESPECIALLY AS LOW-LEVEL LAPSE RATES
STEEPEN DURING THE AFTERNOON.
Quoting Storm-
QUOTE (Stormchaser @ Jun 5 2010, 01:52 PM) 
Very impressive looking picture for tomorrow afternoon, potentially, dare I say it, one of the better threats in awhile for tomorrow. Assuming we can get some morning destabilization via sunshine, temps into the low-mid 80s w/ TD's near 70, MUCAPE values should surpass 1500-2000 J/KG, maybe up to 2500 J/KG. This coupled with strong shearing of 55-65 kts via the mid level jet and pressure falls associated with the surface low, should be sufficient for widespread convection in the forms of multicellular clusters, bow echos producing wind damage, or a few isolated supercells. As you know supercells in the Northeast are akin to snowstorms in Norfolk VA, so approach with caution. Helicity is extremely favorable, 400 m2/s2, meaning there's plenty of turning winds as we head up in the atmosphere, conducive for wall clouds, funnel clouds, or isolated weak tornado development. My main concern is wind damage in the forecasted environment but be on the look out for some scary looking cloud formations tomorrow afternoon.
What can go wrong -- morning convection could be ongoing in PA, and if the cloud debris and residual weakening T-storms impact us late tonight or tomorrow morning, that could put a damper on destabilization and thus afternoon severe weather opportunity. IMO severe t-storm forecasting is probably the most difficult out of any type of weather, even harder than winter storm forecasting. So many different variables that can affect the outcome.
What can go wrong -- morning convection could be ongoing in PA, and if the cloud debris and residual weakening T-storms impact us late tonight or tomorrow morning, that could put a damper on destabilization and thus afternoon severe weather opportunity. IMO severe t-storm forecasting is probably the most difficult out of any type of weather, even harder than winter storm forecasting. So many different variables that can affect the outcome.
