Eskimo Joe Posted July 9, 2023 Share Posted July 9, 2023 Updated LWX AFD: Quote AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1042 AM EDT SUN JUL 9 2023 .SYNOPSIS... A COLD FRONT WILL APPROACH THE AREA TODAY, BEFORE PROGRESSING OFF TO THE SOUTHEAST ON MONDAY. THEREAFTER, HIGH PRESSURE WILL BUILD INTO THE AREA THROUGH THE MIDDLE OF THE WEEK. ANOTHER COLD FRONT WILL STALL NORTHWEST OF THE AREA DURING THE SECOND HALF OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... MID-MORNING UPDATE: CONFIDENCE IS INCREASING THAT THAT THE GREATEST THREAT FOR SEVERE THUNDERSTORMS, AND ESPECIALLY FLASH FLOODING MAY BE FROM THE BALTIMORE METRO AREA NORTH AND EAST. RECENT CAM GUIDANCE SHOWS A WEAK SURFACE LOW DEVELOPING THIS AFTERNOON IN THE VICINITY OF THE DC METRO AND THEN TRACKING SLOWLY OFF TOWARD THE EAST. LOW-LEVEL CONVERGENCE AND POTENTIAL FOR TRAINING CELLS WOULD BE MAXIMIZED TO THE NORTH OF THIS DEVELOPING SURFACE LOW, AND NEARLY ALL OF THE 12Z CAMS SUPPORT HAVING THE GREATEST RAINFALL TOTALS FROM THE BALTIMORE METRO NORTH AND EAST. ALSO OF NOTE IS THAT SOME SHOWERS ARE ALREADY DEVELOPING AND FEEDING IN OFF OF THE BAY THIS MORNING. SOME CAM SOLUTIONS SUPPORT FURTHER DEVELOPMENT IN THIS AREA OVER THE NEXT SEVERAL HOURS, LEADING TO THE POTENTIAL FOR MULTIPLE ROUNDS OF RAIN THERE. THE GREATEST SURFACE HEATING HAS ALSO BEEN FROM THE DC METRO NORTH AND EAST. TO THE SOUTH AND WEST OF DC, MORE SUBSTANTIAL CLOUD COVER HAS BEEN PRESENT, WHICH HAS LIMITED DAYTIME HEATING AND RESULTANT SURFACE DESTABILIZATION. THIS CASTS SOME UNCERTAINTY REGARDING THE DEVELOPMENT OF STRONGER STORMS TO THE SOUTH AND WEST OF DC. RECENT CAM RUNS HAVE BACKED OFF ON RAINFALL TOTALS IN THOSE LOCATIONS, WHICH SEEMS PLAUSIBLE GIVEN CURRENT OBSERVATIONS. AN EXTENSIVE AREA OF RAIN, WITH A FEW EMBEDDED THUNDERSTORMS IS PRESENT OVER THE CENTRAL SHENANDOAH VALLEY AND THE POTOMAC HIGHLANDS AT THE MOMENT. AS THIS AREA OF RAIN PROGRESSES EAST, THUNDERSTORM DEVELOPMENT IS EVENTUALLY EXPECTED ALONG THE LEADING EDGE, WITH THE HIGHEST CONFIDENCE IN STORM COVERAGE ACROSS NORTHEASTERN MD. PREVIOUS DISCUSSION FOLLOWS... AN ACTIVE WEATHER DAY IS STILL ON TAP AS A COLD FRONT AND UPPER LEVEL TROUGH APPROACH FROM THE WEST. FLASH FLOODING AND SEVERE WEATHER WILL BOTH BE CONCERNS. HOWEVER, THE EVOLUTION OF THE EVENT IS STILL NOT CLEAR. EARLY THIS MORNING, THE LOCAL AREA IS DRY WITH SOME PATCHY FOG IN THE VIRGINIA PIEDMONT WHERE SKIES HAVE CLEARED. CONVECTION IS ONGOING ACROSS THE MID OHIO VALLEY ASSOCIATED WITH A WEAKER LEAD PERTURBATION. THIS ACTIVITY APPEARS TO BE ADVANCING TOWARD US A BIT QUICKER THAN MOST GUIDANCE INDICATES, WHICH COULD HAVE SOME DOWNSTREAM EFFECTS AS MOST GUIDANCE BLOSSOMED THIS ACTIVITY INTO THE "MAIN EVENT." AN EARLIER ARRIVAL TIME BEFORE STRONG HEATING CAN OCCUR MAY TEMPER THE SEVERE WEATHER THREAT SOMEWHAT. IF THE STORMS ARE ABLE TO ORGANIZE WITH SOMEWHAT MODEST WIND FIELDS, DAMAGING GUSTS WOULD BE MOST LIKELY EAST OF THE BLUE RIDGE. THE FLASH FLOOD THREAT STILL LOOKS RELEVANT REGARDLESS OF TIMING WITH A MOISTURE RICH AIRMASS IN PLACE. EVEN THOUGH THE BAND OF STORMS SHOULD BE PROGRESSIVE TO THE EAST, WINDS THAT WILL BE LARGELY PARALLEL TO THE BAND COULD PROMOTE INDIVIDUAL CELLS TO TRAIN BRIEFLY. GUIDANCE CONTINUES TO SHOW A SIGNAL THAT THE GREATEST RISK FOR LOCALLY HIGHER RAIN TOTALS IN EXCESS OF 3 INCHES IN NORTH CENTRAL AND NORTHEAST MARYLAND, WHERE SOME CONVECTION MAY TAKE LONGER TO CLEAR. A MORE SIGNIFICANT INSTANCE OF FLASH FLOODING CAN'T BE RULED OUT, AND WPC HAS THIS AREA IN A MODERATE RISK FOR EXCESSIVE RAINFALL. A QUICKER TIMING FOR THE FIRST ROUND MAY ALLOW SOME CLEARING AND DESTABILIZATION FOR AREAS NEAR AND WEST OF THE BLUE RIDGE BY MID TO LATE AFTERNOON AHEAD OF THE APPROACHING PRIMARY TROUGH AXIS. ADDITIONAL SCATTERED STORMS MAY DEVELOP IN THIS REGION. IT'S QUESTIONABLE HOW MUCH INSTABILITY WILL BE ABLE TO DEVELOP, BUT IT'S NOT OUT OF THE QUESTION A FEW STRONG TO SEVERE STORMS COULD DEVELOP IN THIS PART OF THE REGIME AS WELL. A HEALTHY SUBSET OF RECENT GUIDANCE KEEPS A THREAT FOR SHOWERS AND PERHAPS A FEW STORM CONTINUING ACROSS THE AREA TONIGHT AS THE TROUGH AND SPEED MAX ALOFT PIVOT ACROSS THE AREA. IT DOES SEEM AS THOUGH THE HEAVY RAIN THREAT SHOULD SUBSIDE THOUGH AS INSTABILITY WANES AND THE RICHER MOISTURE DEPARTS TO THE EAST. TEMPERATURES WILL BE HELD BACK BY CLOUD COVER TODAY, ONLY REACHING THE LOWER TO MID 80S. 1 Link to comment Share on other sites More sharing options...
aldie 22 Posted July 9, 2023 Share Posted July 9, 2023 I like checking the weather underground site for my location for chits and giggles. This morning it said 100% chance storms up to .71 of rain then it said 56% chance .34 then 34% and .04 now says 17% and 0.0. Radar has that skip it look to it. Good luck to anyone who gets it. 1 Link to comment Share on other sites More sharing options...
BlizzardNole Posted July 9, 2023 Share Posted July 9, 2023 2 minutes ago, Eskimo Joe said: Updated LWX AFD: .NEAR TERM /THROUGH TONIGHT/... MID-MORNING UPDATE: CONFIDENCE IS INCREASING THAT THAT THE GREATEST THREAT FOR SEVERE THUNDERSTORMS, AND ESPECIALLY FLASH FLOODING MAY BE FROM THE BALTIMORE METRO AREA NORTH AND EAST. Well I and my fellow desert rats are just shocked! My bar is a half inch and one rumble of pity thunder but that will take some luck Link to comment Share on other sites More sharing options...
Eskimo Joe Posted July 9, 2023 Share Posted July 9, 2023 Pretty safe to say some of the CAMs are busting hard and seem to be underestimating the morning activity. HRRR appears to have missed all of the pre-game convection from I-83 northeast into PA. 1 Link to comment Share on other sites More sharing options...
Terpeast Posted July 9, 2023 Share Posted July 9, 2023 Most mesoscale models want to dry out radar sim east of blue ridge after 18z and reignite convection baltimore north Link to comment Share on other sites More sharing options...
osfan24 Posted July 9, 2023 Share Posted July 9, 2023 14 minutes ago, BlizzardNole said: .NEAR TERM /THROUGH TONIGHT/... MID-MORNING UPDATE: CONFIDENCE IS INCREASING THAT THAT THE GREATEST THREAT FOR SEVERE THUNDERSTORMS, AND ESPECIALLY FLASH FLOODING MAY BE FROM THE BALTIMORE METRO AREA NORTH AND EAST. Well I and my fellow desert rats are just shocked! My bar is a half inch and one rumble of pity thunder but that will take some luck Seems pretty obvious just looking at radar, though I would say PA and north. Even Baltimore is missing a lot of that pre-front activity that’s popping ahead of the main line. Link to comment Share on other sites More sharing options...
nj2va Posted July 9, 2023 Share Posted July 9, 2023 Over 1” here so far. Way more than forecast. Link to comment Share on other sites More sharing options...
Jrlg1181 Posted July 9, 2023 Share Posted July 9, 2023 15 minutes ago, BlizzardNole said: .NEAR TERM /THROUGH TONIGHT/... MID-MORNING UPDATE: CONFIDENCE IS INCREASING THAT THAT THE GREATEST THREAT FOR SEVERE THUNDERSTORMS, AND ESPECIALLY FLASH FLOODING MAY BE FROM THE BALTIMORE METRO AREA NORTH AND EAST. Well I and my fellow desert rats are just shocked! My bar is a half inch and one rumble of pity thunder but that will take some luck Yeah , despite what the radar is showing down here, official total so far is .0000.... some spots are going to end up with very little.. Link to comment Share on other sites More sharing options...
BlizzardNole Posted July 9, 2023 Share Posted July 9, 2023 A rainfall map showing the stark differences in totals in our region from June 1 thru end of today will be unbelievable. Mostly cloudy and humid as I did some gardening work. I'll be running the sprinklers tomorrow morning Link to comment Share on other sites More sharing options...
Terpeast Posted July 9, 2023 Share Posted July 9, 2023 Looks like a split between MD north and central VA south as per radar evolution… Link to comment Share on other sites More sharing options...
MN Transplant Posted July 9, 2023 Share Posted July 9, 2023 11 minutes ago, BlizzardNole said: A rainfall map showing the stark differences in totals in our region from June 1 thru end of today will be unbelievable. Mostly cloudy and humid as I did some gardening work. I'll be running the sprinklers tomorrow morning 1 Link to comment Share on other sites More sharing options...
MN Transplant Posted July 9, 2023 Share Posted July 9, 2023 2 minutes ago, Terpeast said: Looks like a split between MD north and central VA south as per radar evolution… This was a PA show all along, with some northern MD areas also cashing in. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted July 9, 2023 Share Posted July 9, 2023 Another watch box coming: https://www.spc.noaa.gov/products/md/2023/md1474.html 1 Link to comment Share on other sites More sharing options...
Eskimo Joe Posted July 9, 2023 Share Posted July 9, 2023 Sever Thunderstorm Watch until 8pm being issued for most of DC/Baltimore metro. 2 Link to comment Share on other sites More sharing options...
Terpeast Posted July 9, 2023 Share Posted July 9, 2023 4 minutes ago, Eskimo Joe said: Sever Thunderstorm Watch until 8pm being issued for most of DC/Baltimore metro. Interesting. Not long after I noted a possible gap in radar. I haven’t looked at spc meso, so there must be something that persuaded them to put up a watch soon Link to comment Share on other sites More sharing options...
Eskimo Joe Posted July 9, 2023 Share Posted July 9, 2023 Mesoscale disco for Baltimore metro and points NE: https://www.spc.noaa.gov/products/md/2023/md1475.html CC: @mappy @toolsheds @psuhoffman 2 Link to comment Share on other sites More sharing options...
North Balti Zen Posted July 9, 2023 Share Posted July 9, 2023 1 hour ago, WxUSAF said: I-83 jackpot zone ya think? Been slow to start here - the action has been north into PA Link to comment Share on other sites More sharing options...
Eskimo Joe Posted July 9, 2023 Share Posted July 9, 2023 20 minutes ago, Terpeast said: Interesting. Not long after I noted a possible gap in radar. I haven’t looked at spc meso, so there must be something that persuaded them to put up a watch soon Low level lapse rates are pretty decent (approaching 8c/km) and DCAPE is nearing 900j/kg in the watch area. IMO, definitely a wet microburst risk. 1 Link to comment Share on other sites More sharing options...
mappy Posted July 9, 2023 Share Posted July 9, 2023 20 minutes ago, Eskimo Joe said: Mesoscale disco for Baltimore metro and points NE: https://www.spc.noaa.gov/products/md/2023/md1475.html CC: @mappy @toolsheds @psuhoffman Thanks, off/on heavy rain/thunder for a couple hours now Link to comment Share on other sites More sharing options...
Wxtrix Posted July 9, 2023 Share Posted July 9, 2023 .08”, sun coming out again. truly depressing. Link to comment Share on other sites More sharing options...
Terpeast Posted July 9, 2023 Share Posted July 9, 2023 5 minutes ago, Eskimo Joe said: Low level lapse rates are pretty decent (approaching 8c/km) and DCAPE is nearing 900j/kg in the watch area. IMO, definitely a wet microburst risk. A few small cells appearing on my doorstep, will report back on how that evolves Link to comment Share on other sites More sharing options...
H2O Posted July 9, 2023 Share Posted July 9, 2023 Looking at radar it seems like DC split forming. Beltway N in MD and Stafford S in Va best spots Link to comment Share on other sites More sharing options...
North Balti Zen Posted July 9, 2023 Share Posted July 9, 2023 7 minutes ago, mappy said: Thanks, off/on heavy rain/thunder for a couple hours now literally just a few sprinkles here 5 miles to your slight SE. That's amazing. Link to comment Share on other sites More sharing options...
aldie 22 Posted July 9, 2023 Share Posted July 9, 2023 Getting some windswept drizzle at the moment Link to comment Share on other sites More sharing options...
Jrlg1181 Posted July 9, 2023 Share Posted July 9, 2023 Really did get shutout, monthly total remains 0.53 and that was mainly last Saturday.. 0.02 last 8 days. Link to comment Share on other sites More sharing options...
mappy Posted July 9, 2023 Share Posted July 9, 2023 10 minutes ago, North Balti Zen said: literally just a few sprinkles here 5 miles to your slight SE. That's amazing. It’s been hit and miss up here too, but there’s lots on radar just to your south, plus the line to our west. You’ll get rain Link to comment Share on other sites More sharing options...
Weather Will Posted July 9, 2023 Share Posted July 9, 2023 Little wind, little lightning, brief rain....lot of hype. Link to comment Share on other sites More sharing options...
aldie 22 Posted July 9, 2023 Share Posted July 9, 2023 Radar says not your day son maybe next time Link to comment Share on other sites More sharing options...
CAPE Posted July 9, 2023 Share Posted July 9, 2023 86 sunny and sultry here. Next few hours should be interesting. Glad I had an inch+ yesterday though! 2 Link to comment Share on other sites More sharing options...
Terpeast Posted July 9, 2023 Share Posted July 9, 2023 Got skipped. Mod rain with gusty winds. No real impact on dry ground. I’ll water the garden tomorrow. Link to comment Share on other sites More sharing options...
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