Kmlwx Posted July 25, 2014 Share Posted July 25, 2014 Discuss here because the severe thread is long and we are within day 3 range at this point. SREF is spitting out some impressive numbers already Link to comment Share on other sites More sharing options...
yoda Posted July 25, 2014 Share Posted July 25, 2014 Moving the afternoon AFD from LWX into here... it discussed the threat nicely AREA FORECAST DISCUSSIONNATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC254 PM EDT FRI JUL 25 2014.NEAR TERM /THROUGH SATURDAY/...HIGH PRESSURE IS IN CONTROL TODAY AND DRY CONDITIONS WILLPERSIST. TEMPS WILL CONTINUE TO RISE INTO THE UPPER 70S IN THEMTNS TO THE LOW 80S NEAR THE INTERSTATE 95 CORRIDOR. HIGH PRESSUREWILL MOVE OFF THE COAST TONIGHT AND WINDS WILL BECOME SRLYTONIGHT. DEWPTS WILL BEGIN TO INCREASE INTO SATURDAY.HIGH PRESSURE WILL BE WELL OFF THE EAST COAST SATURDAY MORNING ANDSRLY FLOW WILL CONTINUE TO DRAW IN HIGHER DEWPTS AS WELL AS WARMERTEMPS. FCST MAX TEMPS WILL REACH THE MID TO UPPER 80S SATURDAYAFTERNOON. WESTERLY FLOW ALOFT WILL LEAD TO UPSTREAM DISTURBANCESREACHING THE MID-ATLANTIC AND A LEE TROUGH TO FORM. A SHORTWAVETROUGH CURRENTLY RESPONSIBLE FOR SHOWERS AND THUNDERSTORMS ACROSSIA-IL WILL REACH THE AREA SATURDAY AFTERNOON. IT IS EXPECTED TOWEAKEN BUT WITH THE SRLY FLOW ADVECTING WARM AND MOIST CONDITIONSINTO THE REGION A FEW SHOWERS WILL BE POSSIBLE IN THE HIGHLANDSAND AHEAD OF THE LEE TROUGH. AN ISOLATED THUNDERSTORM WILL BEPOSSIBLE ACROSS THE I-95 CORRIDOR SAT AFTERNOON. ACTIVITY WILLWANE TOWARDS SUNSET.A STRONG SHORTWAVE TROUGH WILL DROP INTO THE NRN PLAINS SATURDAYWHILE CONVECTION WILL BE ONGOING AHEAD OF A COLD FRONT ACROSS THEMIDWEST SATURDAY AFTERNOON AND EVENING. SOME SHOWERS ANDTHUNDERSTORMS ARE EXPECTED TO BECOME SEVERE AND THIS ACTIVITY WILL PROPAGATEEASTWARD AND POTENTIALLY IMPACT THE POTOMAC HIGHLANDS LATESATURDAY NIGHT/EARLY SUNDAY MORNING. THERE ARE UNCERTAINTIESPERTAINING TO THE TRACK OF A POTENTIAL MCS SUNDAY MORNING WHICHWILL THEN IMPACT THE AMT OF CLOUD COVER AND THEREFORE INSTABILITYTHE MID- ATLANTIC GAINS ON SUNDAY.&&.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...A WARM FRONT WILL MOVE ACROSS THE REGION SATURDAY NIGHT/SUNMORNING AND MOISTURE WILL CONTINUE TO ADVECT INTO THE MID-ATLANTICSUNDAY. LOW PRESSURE WILL BE ACROSS THE GREAT LAKES AND A COLDFRONT WILL BE STRETCHED FROM PA TO OHIO TO MO. AS THE STRONGSHORTWAVE TROUGH NEARS SHEAR WILL INCREASE AND SHOWERS ANDTHUNDERSTORMS ARE LIKELY. DEPENDING ON THE AMT OF INSTABILITY THEREGION GETS WITH THE DEPARTING MCS FROM THE OHIO VALLEY... SEVERESTORMS MAY BE POSSIBLE WITH THE THREATS OF DMG WINDS LARGE HAILISOLATED TORNADOES AND HEAVY RAIN. SREF ENSEMBLE MEMBERS SHOW ARANGE OF CAPE SOLUTIONS FOR SUNDAY WITH 500 TO 3000 J/KG POSSIBLE.ONE THING THAT IS CERTAIN IS THAT SHEAR PROFILES INCREASE SUNDAYAND HODOGRAPHS BECOME LINEAR WITH 40-50 KTS AT 10-15K FEET. ASTRONG LINE OF THUNDERSTORMS WILL BE POSSIBLE SUN AFTERNOON ANDEVENING.OUTFLOW BOUNDARIES AND THE CLOSE PROXIMITY TO THE SFC LOW ACROSSOH/PA/NY WILL LEAD TO THE THREAT OF SVR THUNDERSTORMS CAPABLE OFPRODUCING TORNADOES. Link to comment Share on other sites More sharing options...
Kmlwx Posted July 25, 2014 Author Share Posted July 25, 2014 Don't care much about Saturday at this point - more interested in Sunday but I guess something sneaky could happen Sat PM. Link to comment Share on other sites More sharing options...
StudentOfClimatology Posted July 25, 2014 Share Posted July 25, 2014 After Wednesday's debacle, I'm seriously craving an uber downburst. Throw in some baseballs and a few 'naders and I'll be ready for winter. Link to comment Share on other sites More sharing options...
dailylurker Posted July 25, 2014 Share Posted July 25, 2014 Sorry, a off topic question. I was on fort Foote road, in Fort Washington today (next to national harbor). I noticed a LOT of tree damage in a small area. Looks like about a month old. Downburst? Link to comment Share on other sites More sharing options...
SLPressure Posted July 26, 2014 Share Posted July 26, 2014 Sorry, a off topic question. I was on fort Foote road, in Fort Washington today (next to national harbor). I noticed a LOT of tree damage in a small area. Looks like about a month old. Down burst? About a month, or 5 or 6 weeks ago, a storm system came through Belle Haven in Va. and crossed over the river in MD. This storm caused major damage in Belle Haven and then in the Ft. Washington area of PG county. A powerful downburst created a lot of havoc in the area. I personally spent 10 afternoons with a chainsaw clearing debris. Link to comment Share on other sites More sharing options...
dailylurker Posted July 26, 2014 Share Posted July 26, 2014 Awesome! Thanks for the explanation. I couldn't believe the amount of damage to the trees. Piles of tree debris still along the streets. Link to comment Share on other sites More sharing options...
mattie g Posted July 26, 2014 Share Posted July 26, 2014 So...what is "supercell composite parameter?" Link to comment Share on other sites More sharing options...
andyhb Posted July 26, 2014 Share Posted July 26, 2014 So...what is "supercell composite parameter?" http://www.spc.noaa.gov/sfctest/help/help_scp.html Effective bulk wind difference is the same thing as effective shear for those who haven't seen it termed as such. Link to comment Share on other sites More sharing options...
andyhb Posted July 26, 2014 Share Posted July 26, 2014 Lol the 00z NAM is one of those runs where the MA severe crew dreams it is right for Sunday. Link to comment Share on other sites More sharing options...
yoda Posted July 26, 2014 Share Posted July 26, 2014 00z NAM - Link to comment Share on other sites More sharing options...
yoda Posted July 26, 2014 Share Posted July 26, 2014 Lol the 00z NAM is one of those runs where the MA severe crew dreams it is right for Sunday. oh hai der Link to comment Share on other sites More sharing options...
Kmlwx Posted July 26, 2014 Author Share Posted July 26, 2014 The most recent SREF run on SPC site is less impressive. Crossing my fingers for actual interesting weather. It will probably fail... Link to comment Share on other sites More sharing options...
andyhb Posted July 26, 2014 Share Posted July 26, 2014 The most recent SREF run on SPC site is less impressive. Crossing my fingers for actual interesting weather. It will probably fail... Areas further west into WV and the mid/upper OH Valley are definitely a better play on Sunday than the MA. The NAM's track record this Spring/Summer has been enough to toss it most times. Link to comment Share on other sites More sharing options...
Kmlwx Posted July 26, 2014 Author Share Posted July 26, 2014 Areas further west into WV and the mid/upper OH Valley are definitely a better play on Sunday than the MA. The NAM's track record this Spring/Summer has been enough to toss it most times. sad face Link to comment Share on other sites More sharing options...
yoda Posted July 26, 2014 Share Posted July 26, 2014 ML Lapse Rates better on 00z GFS than 00z NAM at 00z MON for KIAD... 6.5 to 7.0 C/KM... GFS has LCL height at just under 400m Link to comment Share on other sites More sharing options...
andyhb Posted July 26, 2014 Share Posted July 26, 2014 30% hatched D2 with a mod risk to the west, full spectrum of severe hazards mentioned with the convective signal across the suite being highlighted. Sunday could be quite an impressive day with multiple areas of enhanced potential. An anomalous setup with a powerful upper trough like this in July certainly has the potential to be a showstopper. Link to comment Share on other sites More sharing options...
EasternUSWX Posted July 26, 2014 Share Posted July 26, 2014 Wow spc going all out. Already near moderate at 1st day 2 update. First big threat of the season. Link to comment Share on other sites More sharing options...
Hoosier Posted July 26, 2014 Share Posted July 26, 2014 DAY 2 CONVECTIVE OUTLOOK AMEND 1 NWS STORM PREDICTION CENTER NORMAN OK 0106 AM CDT SAT JUL 26 2014 VALID 271200Z - 281200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF ERN KY...SRN OH...AND WV... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OH/TN VALLEYS EWD ACROSS THE MID ATLANTIC AND NEW ENGLAND STATES... AMENDED FOR SIG GRAPHIC ...SUMMARY... TORNADOES...DAMAGING WINDS AND LARGE HAIL ARE EXPECTED ACROSS MUCH OF EASTERN KENTUCKY...SOUTHERN OHIO AND WEST VIRGINIA DURING THE AFTERNOON AND EVENING. SEVERE WEATHER IS ALSO EXPECTED ACROSS MUCH OF THE MID-ATLANTIC AND NORTHEASTERN STATES WITH MAINLY DAMAGING WINDS AND HAIL. ISOLATED HAIL AND WIND IS ALSO POSSIBLE ACROSS SOUTHEASTERN ARIZONA. ...SYNOPSIS... AN IMPRESSIVE UPPER TROUGH WILL DIVE SEWD FROM THE UPPER MS VALLEY INTO THE OH VALLEY ON SUNDAY WITH MID TO UPPER LEVEL WINDS INCREASING TO 60-90 KT RESPECTIVELY. AT THE SURFACE...THE PRIMARY SURFACE LOW WILL TAKE SHAPE FROM LOWER MI INTO OH DURING THE DAY...WITH SURFACE TROUGH/FRONT FROM OH SWWD ALONG THE OH RIVER. PRECEDING THE COLD FRONT WILL BE CLUSTERS OF STORMS...PERHAPS A SEVERE MCS...OVER SRN OH/WV/ERN KY IN THE MORNING...AND THIS MAY AFFECT VA LATER IN THE DAY. OUTFLOW FROM THIS POTENTIAL MCS MAY AID TORNADO POTENTIAL ACROSS THE MDT RISK AREA LATER IN THE DAY WHEN WSWLY SURFACE WINDS AND COOLING ALOFT STRONGLY DESTABILIZE THE AREA. TO THE E...A SURFACE TROUGH WILL ALSO DEEPEN E OF THE APPALACHIANS WITH S WINDS BRINGING ATLANTIC MOISTURE NWD ACROSS THE DELMARVA AS WELL AS INTO SRN NEW ENGLAND DURING THE DAY. AN UPPER-LEVEL DISTURBANCE MAY AID IN RELATIVELY EARLY SEVERE STORM DEVELOPMENT FROM ERN NY INTO SRN NEW ENGLAND WITH A SECOND ROUND OF STORMS OCCURRING OVERNIGHT. MOISTURE AND LIFT WITH A WWD-MOVING DISTURBANCE ACROSS NRN MEXICO/SRN AZ MAY RESULT IN ISOLATED HAIL OR WIND. ...ERN INDIANA...CNTRL AND ERN KY...OH...WV... A MORNING MCS IS LIKELY TO TRAVERSE THIS AREA AND MOST LIKELY AFFECT THE SRN OH/ERN KY/WV AREA IN THE MORNING WITH AN ONGOING WIND THREAT. BEHIND THIS SYSTEM...THE VEERED NATURE OF THE LOW-LEVEL FLOW SHOULD ALLOW FOR RAPID DESTABILIZATION WITH UPPER 60S/LOWER 70S F DEWPOINTS AS WELL AS EVENTUAL COOLING ALOFT WITH THE UPPER TROUGH. AS FORCING FOR ASCENT INCREASES DURING THE AFTERNOON...STORMS SHOULD FORM ALONG THE FRONT OVER ERN IND...WRN OH...AND INTO NRN KY...MATURING AS THEY MOVE ESEWD INTO ERN KY...SRN OH...AND AGAIN WV. STEEP LAPSE RATES ALOFT AND LONG HODOGRAPHS WILL SUPPORT ROBUST SUPERCELLS WITH VERY LARGE HAIL LIKELY. RELATIVELY LOW LCLS AND ENHANCED SRH MAY ALSO SUPPORT AN APPRECIABLE TORNADO THREAT. A STRONG TORNADO OR TWO MAY OCCUR...ALTHOUGH THE PRECISE AREA WILL NOT BE KNOWN UNTIL THE MORNING ACTIVITY DEPARTS AND MESOSCALE BOUNDARIES SETUP. ...WV INTO PA AND NJ LATE... A SEVERE MCS IS FORECAST TO EVOLVE OUT OF THE MDT RISK AREA...WITH DAMAGING WINDS AND HAIL POSSIBLE ALONG THE LOW TRACK...AIDED BY A STRONG VORT MAX AND ENHANCED CONVERGENCE WITH THE SURFACE LOW. A TORNADO CANNOT BE RULED OUT WITH THIS ACTIVITY DUE TO BETTER LOW-LEVEL SHEAR NEAR THE LOW. ...NRN VA...MD...DE...PA...NJ LATE AFTERNOON THROUGH EVENING... AN MCS IS LIKELY TO BE ONGOING SOMEWHERE NEAR WV SUN MORNING...AND IT IS UNCLEAR WHETHER IT WILL PERSIST INTO VA AND MD DURING THE DAY. EVEN IF IT DOES NOT REMAIN INTACT...OUTFLOW BOUNDARIES...AS WELL AS INCREASING CONVERGENCE WITH THE LEE SURFACE TROUGH SHOULD PROVIDE ADDITIONAL FOCUS FOR SEVERE STORMS BY LATE AFTERNOON. SHEAR PROFILES WILL BECOME QUITE FAVORABLE FOR SUPERCELLS WITH TIME...AND PLENTY OF INSTABILITY WILL BE PRESENT TO SUPPORT THEM. LARGE HAIL WILL BE LIKELY...AND A COUPLE TORNADOES WILL ALSO BE POSSIBLE GIVEN CELLULAR STORM MODE AND MODESTLY-LOOPING HODOGRAPHS. THERE IS A STRONG CONVECTIVE SIGNAL IN SEVERAL MODELS ACROSS MD...ERN VA AND DE NEAR 00Z. Link to comment Share on other sites More sharing options...
yoda Posted July 26, 2014 Share Posted July 26, 2014 Rarely see this around here Link to comment Share on other sites More sharing options...
andyhb Posted July 26, 2014 Share Posted July 26, 2014 sad face While I stand by my above statement, it's not like there would be no potential in the area with what everything else is showing. This is the most impressive threat the region has faced this year. Link to comment Share on other sites More sharing options...
EasternUSWX Posted July 26, 2014 Share Posted July 26, 2014 Chasing looks to be in order. Better call someone to take my shift at work lol. Thinking western Va maybe? Link to comment Share on other sites More sharing options...
Kmlwx Posted July 26, 2014 Author Share Posted July 26, 2014 Wow...not often you see that kind of early day 2 outlook around these parts. Interesting shape to the hatching - 6z NAM looks like it backed off a little bit from last night. Also SREF and NAM continue to focus best parameters just to the south of the DC area. Link to comment Share on other sites More sharing options...
mappy Posted July 26, 2014 Share Posted July 26, 2014 When Midwest/central people show up in a MA thread, it's time to pay attention Link to comment Share on other sites More sharing options...
Kmlwx Posted July 26, 2014 Author Share Posted July 26, 2014 When Midwest/central people show up in a MA thread, it's time to pay attention Ellinwood thinks SPC was a bit on the bullish side given the uncertainty. 6z NAM for us was definitely not like the 0z NAM. He thinks 30% somewhere east of the apps will be needed but still a lot to be worked out. We'll need to see more runs like the NAM of last night if we want to hold higher potential. Link to comment Share on other sites More sharing options...
arlwx Posted July 26, 2014 Share Posted July 26, 2014 From the 3 am AFD from LWX... LONG TERM /SUNDAY THROUGH FRIDAY/...THE PRIMARY ACTION DURG THE XTND PD LOOKS TO BE COMING AT THEBEGINNING. SYNOPTICALLY THIS SUMMER CERTAINLY HAS BEEN OUT OF THENORM (IE..AN ABSENCE OF THE SUB TROP HIGH) AND IT LOOKS LK THIS WLHOLD TRUE FOR THE END OF JUL AS WELL.IT APPEARS THAT AN UNUSUALLY STRONG AREA OF LOW PRES WL BETRACKING ACROSS PA SUN EVE. THIS WL PLACE THE MID ATLC SUN IN ANUNSTABLE AIR MASS W/ CAPES OVR 1000. SPC HAS ENTIRE CWA IN A SLTRISK. ONE THING THAT WOULD MAKE THIS THREAT STRONGER IS IF AREA GETSBRKS IN CLDS DURG MIDDAY TO ALLOW FOR HTG/INSTABILITY. HIGHS SEASONABLE...GNRLY IN U80S...PSBLY 90 IN THE CIITES.CHC FOR RA/TSTMS XPCTD TO CONT SUN NGT AHD OF A CD FNT. HOW MUCHINSTABILITY WL RMN POST-SUNSET WL HELP TO DETERMINE IF THERE WL BEA CONT SVR THREAT. LOWS RANGING FM THE M60S TO L70S.CURRENTLY IF LOOKS LK THE ACTUAL CD FNT WON`T PUSH E OF THE RGNUNTIL LATE MON...HENCE MORE POPS/CHCS FOR CNVCTN. HIGHS IN LM80S. Link to comment Share on other sites More sharing options...
Ian Posted July 26, 2014 Share Posted July 26, 2014 Mod risk or bust. Link to comment Share on other sites More sharing options...
Kmlwx Posted July 26, 2014 Author Share Posted July 26, 2014 Latest SPC SREF maps again taking best parameters to our south. Maybe that hatched area will get shunted south at least a bit on the updated D2. We'll see what the NAM says. Link to comment Share on other sites More sharing options...
Kmlwx Posted July 26, 2014 Author Share Posted July 26, 2014 NAM focuses best stuff south of the area - DC area still gets in on decent parameters, tho...Relative min of CAPE moves through parts of the area on the run as well - I assume caused by overturning from crapvection. Link to comment Share on other sites More sharing options...
Kmlwx Posted July 26, 2014 Author Share Posted July 26, 2014 I'd venture a guess that we'll see the hatched area tweaked a bit south on the afternoon D2 update. Still uncertainty but a lot of the runs really seem to like the focus south. Fringeddddd Link to comment Share on other sites More sharing options...
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