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Mid-June severe threats


Ian

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Until it's here ;)

This past period never looked very good--probably shouldn't have started a thread to keep my good thread streak going. :P I could extend it through the weekend into next week to set it straight. Pattern seems pretty favorable weekend onward for a bit for something to happen.  Thurs has decent shear but doesn't seem we're going to get the instability needed. 

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This past period never looked very good--probably shouldn't have started a thread to keep my good thread streak going. :P I could extend it through the weekend into next week to set it straight. Pattern seems pretty favorable weekend onward for a bit for something to happen.  Thurs has decent shear but doesn't seem we're going to get the instability needed. 

 

I think its more of the MCS or complex that comes through Wed night... not really expecting much for Thursday IMO

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This past period never looked very good--probably shouldn't have started a thread to keep my good thread streak going. :P I could extend it through the weekend into next week to set it straight. Pattern seems pretty favorable weekend onward for a bit for something to happen.  Thurs has decent shear but doesn't seem we're going to get the instability needed. 

Does your gut feeling for the weekend say our "regular" severe events or something potentially a bit more widespread (not talking Ivan style) but something involving more than like 2 gustnaders. We really need to get out of this doldrum of weather we've been in. Hopefully the Ian method of persistence is not going to plague us for the remainder of season. 

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post-397-0-75750000-1434606923_thumb.png

 

 

Once again, SPC hands us a SLGT risk... 2/5/15

 

..OH VALLEY TO MIDDLE ATLANTIC  

 
STRONG SHORT-WAVE TROUGH WILL MIGRATE ACROSS NWRN ONTARIO INTO  
QUEBEC DURING THE DAY ENCOURAGING MODEST WNWLY MID-LEVEL FLOW SWD  
ACROSS THE OH VALLEY/MIDDLE ATLANTIC REGION. ASSOCIATED SFC FRONT  
IS EXPECTED TO PROGRESS TO A POSITION FROM CNTRL LOWER MI...SWWD  
INTO NRN MO BY 18Z...THEN DEEP INTO THE OH VALLEY BY EARLY EVENING.  
THIS BOUNDARY WILL LIKELY SERVE AS THE FOCUS FOR CONVECTIVE  
DEVELOPMENT...WHILE ISOLATED STORMS WILL EVOLVE WELL AHEAD OF THE  
WIND SHIFT INTO PORTIONS OF PA/DELMARVA ALONG WEAK BOUNDARY.  
FORECAST SFC-6KM SHEAR VALUES ARE ON THE ORDER OF 35KT ACROSS THIS  
REGION WHICH SHOULD SUPPORT ORGANIZED UPDRAFTS. WHILE A FEW WEAK  
SUPERCELLS COULD EVOLVE...IT APPEARS PRIMARY CONVECTIVE MODE WILL BE  
ORGANIZED CLUSTERS/LINE SEGMENTS. LOCALLY DAMAGING WINDS ARE THE  
MAIN CONCERN WITH TSTMS THAT SPREAD SEWD FROM THE OH VALLEY TOWARD  

THE MIDDLE ATLANTIC.

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1300 SPC Day 1 OTK Disco... still 2/5/15

 

 


..APPALACHIAN CREST TO TIDEWATER VA    DIFFERENTIAL HEATING ON THE EAST SLOPES OF THE APPALACHIAN HIGHLANDS  WILL SPUR CONVECTIVE DEVELOPMENT BY AFTERNOON AS LOWER ELEVATIONS  BECOME STRONGLY UNSTABLE. BACKGROUND SYNOPTIC ASCENT SHOULD SUSTAIN  CONVECTION EASTWARD AMIDST DEEP-LAYER UNIDIRECTIONAL SHEAR ADEQUATE  FOR UPDRAFT PERSISTENCE/ORGANIZATION. IN ADDITION TO THE POTENTIAL  FOR CLUSTERS AND/OR BROKEN LINES OF STORMS CAPABLE OF SCATTERED  DAMAGING WINDS AND MARGINAL HAIL...CELLS TRACKING NEAR/ALONG  SOUTHEAST TO NORTHWEST ORIENTED BACK-DOOR QUASI-STATIONARY BOUNDARY  OVER THE DELMARVA REGION COULD SPAWN A BRIEF TORNADO OR TWO.
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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1000 AM EDT THU JUN 18 2015

.SYNOPSIS...
A WARM FRONT WILL STALL OUT OVER THE AREA TODAY BEFORE DISSIPATING
TONIGHT. ANOTHER COLD FRONT WILL APPROACH FROM THE NORTH FRIDAY
BEFORE STALLING OUT OVERHEAD FRIDAY NIGHT INTO SATURDAY. THE
REMNANTS FROM BILL WILL PASS THROUGH SATURDAY NIGHT INTO SUNDAY
AND ANOTHER COLD FRONT MAY STALL OUT OVER THE AREA EARLY NEXT
WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
FOG AND LOW CLOUDS WILL CONTINUE TO MIX OUT THIS MORNING. ZONAL
FLOW ALOFT PERSISTS ACROSS THE REGION TODAY. A WARM FRONT EXTENDS
FROM CENTRAL PA ACROSS NE MD AND INTO THE DELMARVA REGION AND
SHOULD STAY STALLED THROUGH THE AFTERNOON. ISO-SCT SHOWERS ARE
EXPECTED IN VICINITY OF THE FRONT MAINLY ACROSS NRN MD TODAY.
BREAKS OF SUNSHINE WILL ALLOW INSTABILITY TO RISE WEST AND SOUTH
OF THE BOUNDARY TODAY...ACROSS MOST OF THE LWX REGION. A SFC
TROUGH IS EXPECTED TO FORM THIS AFTERNOON FROM NEAR THE WESTERN
SHORE OF THE BAY SOUTH NEAR SOUTHERN MD/PIEDMONT. WINDS ALOFT WILL
ALLOW FOR 30-40KT DEEP LAYER SHEAR PROFILES THIS AFTERNOON. THIS
MAY ALLOW FOR STRONG TO SEVERE THUNDERSTORMS IN THE REGION. THE
BEST CHANCE FOR SEVERE WILL BE IN VICINITY OF THE WARM FRONT AND
SFC TROUGH MAINLY EAST OF THE BLUE RIDGE TODAY. DMG WIND GUSTS AND
LARGE HAIL ARE THE MAIN THREATS WITH THE POTENTIAL OF TORNADOES
IF THUNDERSTORMS NEAR THE SFC BOUNDARIES.
FURTHER WEST...WESTERLY
SFC WINDS MAY CAUSE INHIBITION AND WEAKER LAPSE RATES. HOWEVER TERRAIN
CIRCULATIONS MAY CAUSE STORMS TO FORM ALONG DIFFERENTIAL HEATING
BOUNDARIES AND MOVE EASTWARD.

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Looks like one of the big reasons why some of the models don't do much in the area is because of lack of instability. NAM is sitting there with like 3000 SBCAPE while some of the models like the 12z RAP and such don't get us much over 1K. We shall see. It's not particularly sunny here for the time being. 

12Z NAM is pretty silly - gets supercell parameters of 4-8 or so into the area with high CAPE. But at the same time it's sim reflectivity is very depressing for us. 

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12z HI-RES has what looks to be a supercell in C MD at 4pm... pretty strong one at that -- 60 dBz... and then promptly sends it into DC at 5pm

That cell does some interesting movement too on the model. Is heading almost due east and then takes a turn to plunge down the Potomac. 

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Looks like one of the big reasons why some of the models don't do much in the area is because of lack of instability. NAM is sitting there with like 3000 SBCAPE while some of the models like the 12z RAP and such don't get us much over 1K. We shall see. It's not particularly sunny here for the time being. 

12Z NAM is pretty silly - gets supercell parameters of 4-8 or so into the area with high CAPE. But at the same time it's sim reflectivity is very depressing for us. 

 

12z HI-RES NAM looks better for you and me ;)

 

But def agree re instability question -- however, sun is out here and its warming up quickly

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