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yoda

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  1. yoda
    I think some of it will depend on how much sun we get tomorrow morning with regards to cloud debris, as you and others have mentioned. If we can get sun going by like 10am... we might be off to the races. I expect some decent tornado potential tomorrow with the curved hodo's and low LCLs as well.
  2. yoda
    Flood Watch up for I95 corridor from near EZF to DC metro into Baltimore metro this evening into the overnight Flood Watch National Weather Service Baltimore MD/Washington DC 239 PM EDT Sun Aug 6 2023 ...Heavy rainfall will move through the area this evening into the overnight hours leading to scattered instances of flash flooding... DCZ001-MDZ011-013-014-504-506-508-VAZ053>055-527-070245- /O.NEW.KLWX.FA.A.0005.230807T0000Z-230807T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ District of Columbia-Southern Baltimore-Prince Georges-Anne Arundel- Central and Southeast Montgomery-Central and Southeast Howard- Southeast Harford-Fairfax-Arlington/Falls Church/Alexandria-Stafford- Central and Southeast Prince William/Manassas/Manassas Park- Including the cities of Montclair, Rockville, Annapolis, Bowie, Falls Church, Annandale, Lake Ridge, Manassas, Aberdeen, Columbia, Bethesda, Dale City, Laurel, Odenton, Severn, South Gate, College Park, Herndon, Gaithersburg, Reston, Camp Springs, Severna Park, Arnold, Suitland-Silver Hill, Chantilly, Clinton, Alexandria, Silver Spring, Baltimore, Franconia, Falmouth, Greenbelt, Glen Burnie, Woodbridge, Centreville, Ellicott City, Washington, Arlington, and McLean 239 PM EDT Sun Aug 6 2023 ...FLOOD WATCH IN EFFECT FROM 8 PM THIS EVENING TO 2 AM EDT MONDAY... * WHAT...Flash flooding caused by excessive rainfall is possible. * WHERE...Portions of DC, Maryland and northern Virginia, including the following areas: in DC, District of Columbia. In Maryland, Anne Arundel, Central and Southeast Howard, Central and Southeast Montgomery, Prince Georges, Southeast Harford and Southern Baltimore. In northern Virginia, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park, Fairfax and Stafford. * WHEN...From 8 PM this evening to 2 AM EDT Monday. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. * ADDITIONAL DETAILS... - Heavy rainfall moving through with the potential for 1 to 2 inches of rainfall, locally higher, in a short period of time. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information
  3. yoda
    Correct on both counts
  4. yoda
  5. yoda
    45 WIND ADDED ON 1730Z OTLK @high risk @Kmlwx @Eskimo Joe
  6. yoda
    Well written AFD this morning from LWX about Monday SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Monday has the potential to be an impactful SVR wx day across the region as anomalously strong flow for this time of year moves into a favorable airmass. Synoptically, a shortwave trough will be moving through the Ohio Valley during the day on Monday. At the sfc, an area of low pressure will trek from northern Ohio into northwestern PA and western NY Monday afternoon/evening. This area of low pressure is anomalous for this time of year (~1000-1004 mb depending on model of choice) as indicated by NAEFS/EPS CFSR climatology. The associated cold front is forecast to move through the area during peak heating in the afternoon/early evening. Let me preface the further detailed environmental analysis that uncertainty remains regarding how morning cldcvr or convective debris may impact the SVR potential in the afternoon. Latest guidance moves clouds out by mid-late morning and quickly destabilizes the region. Given the dynamics and kinematics at play, a long period of heating may not be necessary for the potential of this event to be realized. From an environmental standpoint, not much has changed. Wind shear will be anomalous/impressive for early August standards (40-60 kts) with lesser, but still notable values of low-level shear. There remains dry air forecast in the mid-levels, which should at least locally enhance the downburst potential given inverted V sounding profiles. Low level lapse rates will be favorable given heating of sfc temps to near 90F. Mid-level lapse rates will be okay for Mid-Atlantic standards (6-6.5C/km). The one observation in hodographs over the past ~24 hours is how the vertical wind profile is not a linear increase in winds with height. Different jet streaks are forecast at different levels between 18-00Z, which is showing up on several models now and causing the hodographs to be wavy in the mid-upper levels. Should this come to fruition, this is not conducive for long- lasting mesocyclones. This may result in a linear storm mode with an embedded TOR threat. Now should the storm initiation be delayed into the 21-03Z window, the potential for mesocyclones becomes more favorable ad the LLJ makes the hodographs wider in the low levels. Will continue to monitor these trends. LCLs are forecast to be rather low which adds confidence to the TOR threat given the wind profiles. In terms of impacts: 1) All modes of SVR wx are possible. While damaging winds are the greatest threat at this time, there is also a tornado and large hail threat. The large majority of the FA is under an Enhanced Risk from SPC west of the Chesapeake Bay. See spc.noaa.gov for the latest SVR wx outlook and probabilities for different phenomena. 2) The seasonably moist airmass will result in torrential rainfall as the storms move through. Rain rates could be high enough to support flash flooding given the forecast 2" PWATs, especially across the DC/Baltimore metro into northeast MD where WPC has a Slight Risk for Excessive Rainfall.
  7. yoda
    Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Aug 06 2023 Valid 071200Z - 081200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL/SOUTHERN APPALACHIANS AND THE MID-ATLANTIC STATES... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SEPARATELY ACROSS THE CENTRAL HIGH PLAINS... ...SUMMARY... Severe thunderstorms are possible Monday across portions of the southern Appalachians, mid-Atlantic and northeast U.S. Scattered swaths of damaging gusts are expected with this activity. Additional widely scattered thunderstorms are possible across the central High Plains, posing a risk for large hail and damaging gusts. ...Synopsis... A potent mid/upper shortwave trough this time of year will shift east from the Mid-MS Valley to the Appalachians on Monday. This will bring a band of anomalously strong west/southwesterly flow to the region, with the strongest flow focused from southern PA southward to northern GA and the Carolinas vicinity. At the surface, low pressure will shift east from northern IL into northern OH through evening, before lifting northeast across the lower Great Lakes overnight. A cold front attendant to the surface low will sweep east/southeast across the Midwest, and become positioned from western NY/PA into northern AL/MS by Tuesday morning. Mid 60s to mid 70s F surface dewpoints are forecast across the large warm sector ahead of the cold front and ejecting mid/upper trough. ...OH Valley to Mid-Atlantic... Some areas of showers and cloudiness are possible early in the day across parts of the Mid-Atlantic vicinity in association with an ejecting lead shortwave impulse, continued warm advection and backed low-level flow to the east of a lee surface trough should keep the atmosphere primed for severe thunderstorm potential during the afternoon/evening. Convection is expected to develop by midday closer to the surface front over parts of OH/KY. Multiple bands of convection are then expected into the afternoon with eastward extent into WV/southern PA and the Delmarva. A mix of semi-discrete cells and clusters are possible initially. A risk for all severe hazards is expected given effective shear greater than 40 kt, effective SRH greater than 200 m2/s2 and MLCAPE 1500-3000 J/kg. With time, upscale growth into a bowing MCS is possible across parts of southern PA/WV and into the Delmarva vicinity, posing an Enhanced risk (level 3 of 5) for severe/damaging gusts during the afternoon/evening. Instability will weaken with northward extent into NY and southern New England. However, isolated strong/severe storms posing a risk mainly for strong gusts and perhaps small hail are expected.
  8. yoda
  9. yoda
    ENH risk trigger pulled for Monday - 5/15/30
  10. yoda
    I've never seen such high numbers of STP that the 18z NAM NEST shows across our area Granted it's just one model run and it'll probably be different at 00z, but 6 to 8? Wow Good amount of PDS TOR tags too on the soundings across the region @high risk @Eskimo Joe @Kmlwx
  11. yoda
    Afternoon AFD from LWX on Monday mentions "volatile potential" Monday looks to be the most impactful of the two days, at least if eerything pans out to support severe weather. The aforementioned trough continues to push through the Ohio Valley Monday, with a pretty potent cold front pushing through our reigon during the afternoon/evening hours. This will be occurring right during peak heating, with temperatures into the low 90s and dew points well into the 70s. Wind shear will be substantial across the region of course, even in the lower levels. With the potential for substantial CAPE, decent mid- level lapse rates by Mid-Atlantic standards, inverted V sounding profiles, and plenty of deep-layer shear, all therats are on the table Monday. Damaging wind gusts will be the primary threat, but could certainly see some large hail as well. Pretty decent low-level flow will be present ahead of the cold front as well, which could even bring an isoalted tornado threat along with the other threats. This could be a volitile day/night across the region, however there remains considerable uncertainty regarding morning cloudcover, upstream convective debris, track of the low, etc. Machine learning continues to show modest probs for SVR wx as well. We will continue to message Monday as low confidence for a potentially higher impact SVR wx event. The greater chances for SVR wx look to be over the northern portions of the area where there is a better overlap in kinematics and dynamics. PWs are anomalous (between 1.75-2" for most), so while the storms may be progressive, cannot rule out some hydro problems near the metros. WPC just upgraded the area to a Slight Risk for excessive rainfall actually, so that further lends confidence to at least some flood threat, particularly in the metros
  12. yoda
    Morning AFD from LWX suggests Sunday and Monday now SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Sunday likely starts out dry as high pressure continue to move off to the east. The focus then turns to the Ohio Valley where multiple disturbances are embedded in the mid-level flow. 00Z guidance has trended upwards in terms of convective coverage Sunday afternoon/evening with the higher focus generally along/west of US-15. This correlates to where SPC has a MRGL (1 out of 5) risk for SVR wx. While the storms should be progressive Sunday during the day, uncertainty arises heading into Sunday evening/night as the warm front is progged to be between the Mason Dixon and Potomac River. Guidance continues to enhance precipitation in this area into PA as the LLJ advects anomalous moisture to the boundary. WPC has a MRGL ERO for most of the CWA, though think the greatest risk is in the aforementioned area. There is a conditional tornado risk Sunday afternoon/evening wherever the warm front does set up. Monday could be an impactful weather day across the region given the anomalous trough moving to the NW and sfc low moving over the Great Lakes into Canada. Most SVR parameters are favorable in our area with a residual lee pressure trough forecast just east of the Blue Ridge to aid the synoptic scale forcing. Hodographs are concerning from model guidance. However, there remains considerable uncertainty regarding morning cldcvr, upstream convective debris, track of the low, etc. Machine learning continues to show modest probs for SVR wx as well. We will continue to message Monday as low confidence for a potentially higher impact SVR wx event. The greater chances for SVR wx look to be over the northern portions of the area where there is a better overlap in kinematics and dynamics. PWs are anomalous (between 1.75-2" for most), so while the storms may be progressive, cannot rule out some hydro problems near the metros. Will continue to monitor, so be sure to check back.
  13. yoda
    Oh....SPC talking dirty in their Day 3 disco this morning SPC AC 050740 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0240 AM CDT Sat Aug 05 2023 Valid 071200Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE SOUTHERN APPALACHIANS...MID-ATLANTIC AND NORTHEAST U.S.... ...SUMMARY... Severe thunderstorms are possible Monday across portions of the southern Appalachians, mid-Atlantic and northeast U.S. ...Mid-Atlantic/northeast... As an upper-level trough moves slowly east across the region Monday, latest deterministic and ensemble guidance suggests a favorably sheared environment for organized severe storms including supercells will exist over a rather large area from the southern Appalachians northeast into the mid-Atlantic/northeast U.S. Heating of a seasonably moist boundary layer, combined with somewhat steeper mid-level lapse rates associated with the eastern fringe of an EML extending east from the southern Plains, will contribute to moderate-strong MLCAPE across the area. Thunderstorms may be ongoing at 12z Monday over portions of PA/NY and vicinity with a weak mid-level impulse and warm advection, and lingering clouds/precipitation will likely influence the degree of destabilization in these areas. Thunderstorms should develop/intensify during the afternoon in advance of a cold front aided by large-scale ascent, with both supercell and multicell storm structures likely. Relatively long hodographs may support splitting storms with a risk for large hail, and seasonably strong low-level wind fields will favor scattered damaging gusts, especially where low-level lapse rates are steepened through stronger heating. A risk for a few tornadoes may also exist, especially across portions of the mid-Atlantic and northeast where low-level hodograph curvature is most pronounced. Have opted to continue a broad 15%/Slight Risk area with this outlook, however higher severe probabilities may ultimately be warranted for portions of the area as mesoscale details come into better focus.
  14. yoda
    Maybe some sneaky severe Sunday? MRGL for i95 and west on new SPC Day 2... 5% wind... but 2% TOR in NW VA into C and W MD
  15. yoda
    Afternoon/evening disco for Monday was well-written on the threats and possible uncertainties .LONG TERM /MONDAY THROUGH FRIDAY/... Monday continues to be shaping up to be a potential impactful weather day with increasing confidence for severe thunderstorms in our forecast area. A strong mid-level trough will eject from the Midwest into the Ohio Valley by Monday. The trough is expected to strengthen and become neutral to negatively tilted during the day on Monday. In response, surface low pressure will develop over Southern Michigan and track into Southern Ontario during the day. Models differ on the idea of a prefrontal shortwave ahead of the trough, which may lead to early convection on Monday out ahead of the main trough. This has led to uncertainty regarding the amount of destabilization. Out ahead of the system, the air mass is expected to become very moist as a result of strengthening southerly winds. Most of the guidance shows precipitable water values near or exceeding 2” east of the Blue Ridge with values over 1.75 west of the Blue Ridge. This increasing moisture advection may lead to low-level clouds and precipitation which may also hinder destabilization during the day, resulting in further uncertainty. Despite the uncertainty, with the trough becoming negatively tilted, mid-level flow is expected to increase across the area with most guidance showing bulk shear values from 30-40 knots. East of the Blue Ridge, there is a stronger signal for increased low-level flow, with soundings showing 0-3 km shear on the order of 20-30 knots which bears watching for potential low-level rotation within some storms. Given the strong forcing and the 30-40 Knots of bulk shear, any sunshine in the afternoon may provide ample instability on the order of around 1000-1500 J/kg of MLCAPE to fuel severe thunderstorms capable of damaging winds, large hail, and even a few isolated tornadoes possible. We will continue to monitor this system as it approaches and uncertainty decreases.
  16. yoda
    While true, I don't think I've seen LWX in their AFD mention tornado threat 4 days out The potential for severe weather is still there, though. Model soundings indicate around 30-40 knots of deep-layer shear will be present over the area. East of the Blue Ridge, 925mb winds around 35KT or greater are resulting in elongated, curved hodographs in the low-levels. If the atmosphere can destabilize, the 1500-2000+ J/kg of SBCAPE is certainly enough to fuel scattered strong to severe thunderstorms. The main threats look to be damaging wind gusts, large hail, and a couple of tornadoes.
  17. yoda
    Afternoon discussion from LWX already talking it up some for Monday On Monday, the aforementioned cold front will approach and move through our area bringing unsettled weather. Confidence continues to increase for severe weather ahead of the frontal passage Monday evening. The most recent guidance continues to indicate bulk shear values between 30-40 knots with CAPE values between 1000-1500 J/kg. Southerly flow ahead of the frontal passage will usher in ample moisture with PWAT values nearing and even exceeding 2 inches along I-95. While the signal for severe weather has persisted for a few days now, uncertainty remains regarding timing due to the system being 5 days away. At this time, damaging winds will likely be the primary threat for Monday. However, large hail and a tornado are possible as well. Isolated instances of flooding are also possible with the moist airmass.We will continue to monitor this system as it approaches.
  18. yoda
    Looking like Monday is our next chance at severe
  19. yoda
    I see DMH is 99 and BWI is 96... so I guess they got the two mixed up
  20. yoda
    CWG tweeted it
  21. yoda
    DCA 97 IAD 98 BWI 99
  22. yoda
    Sigh Broadcast media reports "numerous trees and branches blew down around Dupont Circle, including several on to people"
  23. yoda
    Velocities are 70 to 80mph for a pretty good portion of this line from VA into MD
  24. yoda
    Severe Weather Statement National Weather Service Baltimore MD/Washington DC 519 PM EDT Sat Jul 29 2023 DCC001-MDC033-VAC059-510-292130- /O.CON.KLWX.SV.W.0218.000000T0000Z-230729T2130Z/ District of Columbia DC-Prince Georges MD-Fairfax VA- City of Alexandria VA- 519 PM EDT Sat Jul 29 2023 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM EDT FOR THE SOUTH CENTRAL DISTRICT OF COLUMBIA...WEST CENTRAL PRINCE GEORGES...AND EAST CENTRAL FAIRFAX COUNTIES AND THE SOUTHEASTERN CITY OF ALEXANDRIA... At 518 PM EDT, a severe thunderstorm was located over Friendly, or over National Harbor, moving southeast at 20 mph. THIS IS A DESTRUCTIVE STORM FOR ALEXANDRIA AND WESTERN PRINCE GEORGE`S COUNTY. HAZARD...80 mph wind gusts and quarter size hail. SOURCE...Radar indicated. IMPACT...Expect considerable damage to trees and power lines. Your life is at significant risk if outdoors. In addition to some trees falling into homes, wind damage is possible to roofs, sheds, open garages, and mobile homes. Locations impacted include... Alexandria, Clinton, Fort Washington, Fort Hunt, Groveton, Huntington, National Harbor, Andrews Air Force Base, Camp Springs, Oxon Hill, Hybla Valley, Rosaryville, Friendly, Temple Hills, Marlow Heights, Accokeek, Forest Heights, Tantallon and Jefferson Manor. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. To report severe weather contact your nearest law enforcement agency. They will send your report to the National Weather Service office in Sterling Virginia. && LAT...LON 3879 7711 3884 7704 3880 7682 3868 7698 TIME...MOT...LOC 2118Z 302DEG 17KT 3877 7697 THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...1.00 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...80 MPH
  25. yoda
    Comes from GW Campus mesonet near Georgetown
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