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yoda

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  1. yoda
    Granted its 1km AGL reflectivity and composite reflectivity, but I don't hate what the 18z RRFS is showing between 02z and 06z for the region
  2. yoda
    Fwiw, both 16z and 17z HRRR have an MCS/line/complex come rolling through the region between midnight and 3am. 17z HRRR encompasses more of the region than the 16z run did. Not saying its severe, just something to think about overnight as we watch it develop out to our NW ETA - 18z HRRR same idea... but an hour or so faster
  3. yoda
    Excellent afternoon AFD from LWX for tonight into tomorrow .DISCUSSION... KEY MESSAGE 1...Slight Risk of severe thunderstorms today and Friday. Clouds have readily thinned in the wake of morning shower and thunderstorm activity. This is allowing for temperatures to rise quickly through the 80s to near 90. This heating will play an important role in the potential for severe weather through the evening hours. As of 2:30 PM, a few discrete (transient supercell) thunderstorms had developed over the Shenandoah Valley, and had a history of producing large hail and wind damage. These storms are developing in an area that has been clear since daybreak, and in an area of enhanced low-level convergence due to residual outflow from morning convection to the north, a washed out front, and terrain circulations. Anticipate this activity to continue into the late afternoon hours with a risk of localized damaging wind gusts and large hail. Meanwhile, upstream over the lower Great Lakes and Ohio Valley, a large reservoir of MLCAPE 3000-4000+ J/kg exists. The north end of this CAPE pool lies along the southern edge of the westerlies, with a 100+ kt 300 hPa jet streak and mid-level shortwave impulse located just to the north. This setup is favorable for the development of a Mesoscale Convective Complex (MCS), which is an organized line of thunderstorms that persists for several hours. Locally, mid-level lapse rates of 6.5-7 C/km (per latest mesoanalysis and the KIAD 12Z RAOB) atop a very moist boundary layer with surface dew points well into the 70s F will lead to increasing CAPE despite the late start at surface heating. The question then becomes just how organized upstream storms become, and how stable the boundary layer is heading further into the evening. A more organized and potent line of storms a bit earlier in the evening would result in a notably higher risk for more numerous damaging wind gusts, especially focused along the residual baroclinic zone/theta-e gradient which should lie near the Potomac River/US-50/I-66 this evening. A somewhat slower and/or more disorganized line would result in a lower risk for severe surface gusts, though some isolated damaging winds would still be possible given high CAPE/DCAPE and the shallow nature of the stable layer near the surface. Areas of western Maryland and perhaps into the eastern West Virginia panhandle are most likely to see the storms prior to the onset of appreciable nocturnal boundary layer stability. The area remains in a Slight Risk (level 2 out of 5) for severe weather from SPC as of the midday outlook update, driven mostly by the threat of damaging wind gusts. There is a threat for large hail in stronger cores, though mid-level lapse rates will gradually become less steep tonight. A linear storm mode would tend to be less favorable for large hail production (as opposed to discrete/individual cells), as well. A few discrete cells are possible this evening in weak low-level WAA, however, independent of any linear system that may affect the region. These storms would be most likely to develop over northern and central Virginia into central Maryland along a weak surface trough and the aforementioned moisture/instability gradient. Additional showers and thunderstorms, possibly strong to severe, are anticipated again on Friday. Timing is a bit uncertain given the subtle waves aloft, but increasing low-level convergence paired with another upper impulse may very well result in another round or two of storms with a damaging wind risk. The latest guidance has nudged the threat a bit further north, encompassing areas as far north as I-70 or the Mason-Dixon line (as opposed to I-66/US-50). This will depend on any residual early day clouds or convection, of course.
  4. yoda
    SVR warned for hail to ping pong ball size and winds to 60mph
  5. yoda
    Radarscope claims rotation with the storm out in W VA (near Broadway)
  6. yoda
    ENH risk introduced in PA/OH on 1630z OTLK from SPC
  7. yoda
    https://www.spc.noaa.gov/products/watch/ww0646.html
  8. yoda
    And a Severe Thunderstorm Watch just issued S and SE of there to the Mason Dixon line until midnight
  9. yoda
    Enhanced Risk was added on 1630z OTLK up in PA/NY
  10. yoda
  11. yoda
    Watch up until 5pm URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 643 NWS Storm Prediction Center Norman OK 1140 AM EDT Wed Sep 2 2026 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of District Of Columbia Maryland Northern Virginia The Eastern West Virginia Panhandle Coastal Waters * Effective this Wednesday morning and afternoon from 1140 AM until 500 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A well-organized thunderstorm cluster should continue to pose some threat for scattered damaging winds as it moves quickly southeastward this afternoon. Occasional hail may also occur with the strongest cores.
  12. yoda
    Severe Thunderstorm Watch up for Central and Southern PA until 2pm
  13. yoda
    LWX AFD from this morning does also state severe storms are possible well into the night KEY MESSAGE 1...Daily severe weather threat through the end of the week. Multiple rounds of thunderstorms, some likely severe with damaging winds, are likely today through Friday as upper level disturbances move from the Great Lks into the Mid Atlantic states. Already seen a small cluster of thunderstorms over south central Pennsylvania that will move through the area later this morning. Two additional rounds of thunderstorms seem likely today, one this afternoon, and a second one late this evening into the overnight hours tonight into Thursday. Thunderstorms will ride southeast along and north of a backdoor front currently pushing south through northern VA and southern MD as seen on TDWRs and wind shifts to the NE at IAD and DCA a couple of hours ago. The severe threat will not be necessarily tied to the afternoon and evening hours as record warm nighttime temperatures and high humidity yield strong instability and keep thunderstorms going strong well into the overnight hours. By Friday, cold front should have cleared much of the forecast area causing a stabilizing effect limiting the risk of severe weather, but showers and thunderstorms will still be possible north of the sfc front.
  14. yoda
    1300z SPC OTLK disco says the morning convection is causing question marks for later Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0723 AM CDT Wed Sep 02 2026 Valid 021300Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE NORTHEAST STATES...AND ACROSS PARTS OF MONTANA... ...SUMMARY... Severe thunderstorms are possible across portions of the eastern Great Lakes to the Mid-Atlantic today and tonight. Damaging wind gusts are the main threat, though some large hail and a few tornadoes may also occur. Scattered severe gusts and more sporadic occurrences of large hail appear possible from the northern Rockies into northern High Plains today into night. ...Northeast States... A complex but potentially active convective day is in store for parts of the northeast US today. A fast-moving MCS and associated mid-level shortwave trough is over Lake Michigan. This system is forecast to track rapidly eastward across Lower MI and southwest ON this morning before emerging into western NY/PA this afternoon. A consensus of overnight CAM solutions indicate this will be the focus for strong-severe thunderstorms that track east-southeastward during the afternoon and evening toward the Mid-Atlantic coast. Ample low-level moisture is present in this corridor. This along with daytime heating well into the 80s and steep low-level lapse rates will favor damaging wind gust potential in the strongest storms. A north-south surface boundary is expected to lie from central NY into east-central PA this afternoon, where low-level shear will be locally enhanced to pose some risk of a few tornadoes. The primary uncertainty for a more widespread severe event today is the presence of considerable morning convection currently over northwest PA and western NY. These storms are well-ahead of the main forcing feature, and decrease confidence in significant destabilization over the primary risk area this afternoon. These early storms may pose a damaging wind and hail risk through the day, especially after a few hours of heating.
  15. yoda
    What about the MPAS?
  16. yoda
  17. yoda
    Severe Thunderstorm Watch up until midnight for NE MD and DE URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 638 NWS Storm Prediction Center Norman OK 435 PM EDT Tue Sep 1 2026 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Delaware Northeast Maryland New Jersey Southern New York Central and Eastern Pennsylvania Coastal Waters * Effective this Tuesday afternoon from 435 PM until Midnight EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely Scattered large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Supercell thunderstorms should pose a threat for large hail this afternoon as they track east-southeastward across the northern Mid-Atlantic. The threat for scattered severe/damaging winds should increase this evening as one or more clusters develops. A tornado or two may also occur with any sustained supercell.
  18. yoda
    https://www.spc.noaa.gov/products/md/md2185.html Mesoscale Discussion 2185 NWS Storm Prediction Center Norman OK 0213 PM CDT Tue Sep 01 2026 Areas affected...portions of the Mid-Atlantic Concerning...Severe potential...Watch likely Valid 011913Z - 012115Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorm development is anticipated within the next 1-2 hours across portions of the Mid-Atlantic region. Given a favorable convective environment, storms will likely intensify and pose a severe wind/hail threat through early evening. Watch issuance is likely by 21z (5 PM EDT) as thunderstorms begin to mature. DISCUSSION...Latest GOES day cloud phase imagery depicts towering cumulus on the north/northeastern fringe of a low-level thermal ridge (roughly outlined by the 90 F isotherm) where modest warm advection is promoting ascent. Some lingering inhibition is noted in satellite imagery, but this should continue to erode over the next couple of hours as the diurnal heating maximum approaches. Latest guidance generally depicts deep convective initiation by 20-21 UTC within this regime and potentially along a diffuse frontal boundary draped from southern NY into northern PA. Regional VWPs continue to sample mid-level flow on the order of 35 knots, which is supporting similar effective bulk shear values given somewhat weak near-surface winds. Based on these observations and recent forecast soundings, hodograph elongation appears sufficient for organized convection, including the potential for a few supercells. While discrete modes persist, large hail (potentially up to 1.75 inches) will be possible. A brief tornado may also be possible - particularly across northern NJ/far southern NY near a weak surface trough where low-level veering may be adequate for a localized tornado threat. With time, clustering should promote some degree of upscale growth with an increasing severe wind threat, especially with southward extent into southern NJ and DE where guidance has been consistently showing a signal for clustered/linear storm modes. Given the favorable convective environment, watch issuance will likely be needed as convection begins to intensify. ..Moore/Gleason.. 09/01/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OKX...ALY...PHI...BGM...CTP...LWX...
  19. yoda
    Severe Thunderstorm Watch coming in an hour or two for NE MD and DE potentially per MCD
  20. yoda
    Granted higher chance for this (bolded mine) is to our north Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Tue Sep 01 2026 Valid 021200Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE EASTERN GREAT LAKES INTO MID-ATLANTIC AND OVER THE NORTHERN ROCKIES... ...SUMMARY... Severe thunderstorms are possible across portions of the eastern Great Lakes to the Mid-Atlantic Wednesday into Wednesday night. Damaging wind gusts are the main threat, though some large hail and a few tornadoes may also occur. Widely scattered severe gusts and more sporadic occurrences of large hail appear possible from the northern Rockies into northern High Plains Wednesday afternoon into night. ...Synopsis... A belt of 40-50+ kt mid-level winds will spread from the Great Lakes into the Northeast in tandem with a series of low-amplitude disturbances. Elsewhere, a negatively tilted shortwave trough and attending mid-level jet streak will progress through the northern Rockies Wednesday afternoon and evening. At the surface, the primary baroclinic zone is expected to extend from low pressure over James Bay through the Great Lakes and mid MO Valley into the northern High Plains. A backdoor front/quasi-stationary boundary will reside over the Mid-Atlantic, the specific location of which will be dictated by the extent of outflow associated with early-day storms and the strength of low-level ridging stretching from the Gulf of St. Lawrence through the Northeast. ...Great Lakes into the Mid-Atlantic... As alluded to in the synopsis, thunderstorms may be ongoing at 12Z Wednesday from portions of WI and MI into NY and PA within a zone of forcing for ascent associated with a lead short-wave trough. The strongest storms will be capable of isolated occurrences of large hail and/or damaging winds as they spread east-southeast through the lower Great Lakes and Mid-Atlantic Wednesday morning. In the wake of the early-day convection, prevailing west-northwest mid-level flow will maintain a plume of relatively steep mid-level lapse rates (e.g., 7 C/km) atop boundary layer dewpoints in the upper 60s to low 70s, yielding MLCAPE upwards of 2000-3000+ J/kg by afternoon from lower MI into western parts of NY and PA. Additional thunderstorms are expected during the afternoon from lower MI through the lower Great Lakes, aided by weak disturbances aloft and the moderate to strong instability forecast across the warm sector. The presence of 35-45 kt of effective bulk shear will support organized storm modes including supercells and bowing structures capable of large hail potentially approaching two inches and damaging wind gusts into Wednesday night. Tornado potential will be conditional on storm mode; however, the models do indicate stronger low-level winds and resultant larger SRH developing from southwest ON into NY and PA Wednesday afternoon into evening, where the greatest potential for a few tornadoes will exist.
  21. yoda
    New Day 2 mentions higher chance for large hail and tornadoes SLGT risk moved further south towards RIC
  22. yoda
    Well the NAM only goes out to 84... and IIRC, SPC didnt really focus on our region severe-wise until Thursday and Friday - which is near the end of its run and after.
  23. yoda
    12z NAM soundings seem to like Wednesday evening into Thursday morning (21z to 06z). What i mean is they suggest some significant severe if everything came together
  24. yoda
    Looks like Wednesday to Friday will be our severe weather threat days
  25. yoda
    And the crowd boos Despite the uncertainties, it remains likely that high temperatures will reach the lower to middle 90s for much of the region for much of the new work week. Latest guidance indicates potential for temperatures in the upper 90s to near 100 mid week, so long as it is not disrupted by cloud cover or convection. Depending on smaller scale details, dew points could end up a little higher or lower than currently progged which will ultimately affect how high heat index values get. Values approaching Heat Advisory criteria (100-104 west of the Blue Ridge, 105-109 east of the Blue Ridge) are possible. Temperatures may begin to moderate by next weekend as a cold front crosses the region.
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