Area Forecast Discussion
Issued by NWS Cleveland, OH
Issued by NWS Cleveland, OH
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391 FXUS61 KCLE 071102 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 702 AM EDT Sun Jul 7 2024 .SYNOPSIS... High pressure will be over the Ohio Valley today then shift towards New England on Monday. Moisture from the remnants of Beryl will approach the area towards the middle of the week. && .NEAR TERM /THROUGH MONDAY/... A quiet forecast remains on track for today. Any patchy fog that developed overnight will dissipate through 8-9 AM. Previous discussion... Surface high pressure will be overhead today then shift towards New England on Monday. The airmass is sufficiently dry for only scattered cumulus clouds to develop with no precipitation in the forecast through Monday. Temperatures will trend 2 to 4 degrees warmer today except for locations in NE Ohio and NW Pennsylvania where lake breezes will keep areas from Cleveland to Erie PA with similar temperatures to Saturday. Upper level heights trend upward on Monday in response to the trough deepening across the Upper Midwest. With surface winds out of the south, temperatures will continue to trend warmer with highs in the upper 80s to low 90s. Dewpoints will tend to be near or just above 60 degrees which is typical of summer and will not contribute to noticeable increases to the heat index. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... The middle part of the week is starting to look more interesting, with increasing odds that the remnants of Beryl will impact the region. Of course, details are uncertain at this point given differences with how Beryl will interact with a longwave trough across the central CONUS, but trends point toward tropical moisture at least bringing greater coverage of showers and thunderstorms. Now for a little more detail, surface high pressure over the eastern Great Lakes Monday night will exit offshore Tuesday as a northern stream mid/upper shortwave progresses from the Upper Midwest into eastern Canada. This will drag a cold front into the southern Great Lakes Tuesday, but guidance is coming into agreement that the boundary will stall somewhere near Lake Erie as the dynamics pass mostly north of the region. This will result in less in the way of forcing, therefore reducing the coverage of showers and thunderstorms compared to previous forecasts. There will be some synoptic scale lift on the southern fringe of an 80-90 knot upper level jet streak, and this combined with at least moderate MLCAPE of 1000-1500 J/Kg will allow scattered convection to develop in the afternoon and evening, but not all areas will see rain. An isolated severe storm or two is possible in this pattern, mainly in the form of damaging downburst winds and locally heavy rainfall, since weak mid-level lapse rates will limit hail production, but the severe threat is not looking widespread. Things become more interesting starting Tuesday night. As the aforementioned shortwave moves out across eastern Canada, broad mid/upper troughing over the central CONUS will pick up Tropical Cyclone Beryl and lift it from the lower Mississippi Valley into the southern or western Great Lakes by Wednesday evening. This could spread deeper tropical moisture and anomalously high PWATs over 2 inches northeastward into the region Tuesday night and Wednesday, but the track of the remnant circulation differs in the guidance. The latest NAM and deterministic Canadian runs take the circulation up through Ohio while the ECMWF takes it up through Indiana, and the GFS takes it just east of Chicago. These differences are the result of uncertainty regarding the amplitude of the central CONUS trough which range from an open trough to somewhat of a closed low. The latest QPF forecast from WPC utilizes an ensemble blend which puts the steadiest swath of rainfall across Indiana and Michigan, but there is still room for this to shift farther west or east in time. Regardless, increasing moisture Tuesday night and Wednesday will lead to greater coverage of showers and thunderstorms, so have increasing PoPs during that period. Coverage should be greatest during the day Wednesday as the tropical moisture interacts with diurnal heating. It is worth noting that if the track goes across Indiana and Michigan, enhanced low-level shear in the eastern quadrant could result in low-topped supercells with rotation, so we could see a marginal severe threat Wednesday in addition to locally heavy rainfall. Coverage of precip should gradually lessen Wednesday night as the circulation lifts away from the region. Highs Tuesday will reach the mid/upper 80s, cooling into the low/mid 80s Wednesday, but still humid. Lows Monday night and Tuesday night will stay in the upper 60s/low 70s, with mid/upper 60s Wednesday night. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... There remains some uncertainty with how the upper level pattern will evolve late in the week into next weekend behind the remnants of Beryl. This is due to a quasi Omega block starting to break down allowing the broad longwave trough over the central CONUS to shift east, but the speed in which that happens is uncertain. The deterministic GFS is the slowest since it has more of a closed low over the Upper Midwest compared to a more open trough axis in the other guidance. At this time, stayed with NBM PoPs and temperatures which has seasonably warm and humid conditions and daily chances for scattered showers and thunderstorms as daytime heating interacts with the old frontal boundary in the region. Once the trough lifts out, higher heat over the Rockies and Plains could attempt to spread east later next weekend into the following week, but some form of NW mid/upper flow looks to persist keeping the warmest conditions west of the region. Highs in the upper 70s/low 80s Thursday will warm into the low/mid 80s Friday and mid/upper 80s Saturday. && .AVIATION /12Z Sunday THROUGH Thursday/... High pressure will maintain mostly clear skies today and winds of 10 knots or less through the period. We are seeing a few sites with MVFR visibilities at TAF issuance but these will improve through about 1230Z. Otherwise scattered cumulus clouds are possible this afternoon with mostly clear skies tonight. Westerly winds today will veer to northwesterly at CLE/ERI/YNG this afternoon with a lake breeze, then east to southeast overnight. Outlook...Non-VFR possible in isolated to scattered showers and thunderstorms Tuesday through Thursday. && .MARINE... Mainly quiet conditions will continue on the lake through the period. Light and variable winds today and Monday thanks to high pressure over the southern Great Lakes will turn S to SW Monday night and eventually W late Tuesday with speeds increasing to 10-15 knots as the high shifts east and a cold front sags into the region. Winds will then oscillate between E and NE at 10-15 knots Tuesday night and Wednesday as the remnants of Beryl approaching from the southwest before turning W to NW by Thursday as the system exits to the northeast. Locally higher winds and waves could occur in and near scattered thunderstorms Tuesday and Wednesday. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. NY...None. MARINE...None. && $$ SYNOPSIS...KEC NEAR TERM...KEC SHORT TERM...Garuckas LONG TERM...Garuckas AVIATION...KEC MARINE...Garuckas