Marine Weather and Tide Forecast for Laporte, PA

NEAR TERM /THROUGH TONIGHT/
A spectacular afternoon of almost cloud-free skies, but this time (compared to Sunday) with light and variable winds in close proximity to a ridge of high pressure over the Susquehanna Valley.

Temps are nicely approaching their fcst highs in the upper 60s to around 70F across the Northern Mtns and Laurel Highlands and lower 70s elsewhere.

Fire concerns for the rest of today will be mitigated somewhat by lighter winds today compared to yesterday along with recent rainfall and green-up across southeastern Pennsylvania. As a result, we've opted for no fire weather headlines this afternoon.

Dry conditions with clear to partly cloudy skies continue into tonight. A freshening southerly breeze and some increase in strato cu clouds late will keep temperatures +10 to +20F warmer by daybreak Tuesday compared to this morning.

Although cloud cover increases early Tuesday morning ahead of an approaching upper-level trough tracking north of the area, the entire region should stay rain-free into late Tuesday morning/Tuesday afternoon before convection develops. More on that below.

SHORT TERM /TUESDAY THROUGH WEDNESDAY/
An upper-level trough will push through the Great Lakes Tuesday afternoon and bring a warm front/cold front progression through the Commonwealth on Tuesday afternoon. This warm front is expected to lift north of central Pennsylvania Tuesday morning, allowing for much of the area to have some residence time in the warm sector. This is expected to allow for warmer temperatures, especially across western Pennsylvania where there is higher confidence on the warm sector pushing north/east of the region.
Despite these warmer temperatures, cloud cover is expected to limit instability across the western half of the forecast area; however, increasingly diffluent upper level westerly flow and ample shear/veering wind with height, beneath the right entrance region of a mid/upper-level jet will lead to a notable potential for severe weather with a high shear-low to moderate CAPE environment during the afternoon and evening hours Tuesday.

Current storm mode favors multicell with some supercells likely as hodographs take on a broad loop across the NW half of the CWA by late Tuesday afternoon with 0-1KM EHI values from 2-3.5 M2/S2 across the Central and NW Mtns between 20Z Tue-00Z Wed. Main threats at this time for severe weather will be damaging winds in mini bow echoes within short line segments considering strong, westerly 0-3 KM bulk shear of 40-45 KTS, and large hail, especially across northwest PA. Given the potential for some "right movers" creating significantly better storm relative inflow and lowered pressure/LCLs beneath the strong updrafts, there is risk for a few isolated tornadoes across the NW 1/3 or so of Pennsylvania, especially from 22Z-00Z when LCL heights will be lowering and storms interact with llvl outflow boundaries from the initial convection.

SPC continues to highlight nearly the exact same part of the state with an Enhanced Risk of SVR TSRA (Level 3 out of 5), which happens about 6 times per year on average across Pennsylvania.

Be sure to Have multiple ways to receive warnings and stay weather aware Tuesday afternoon and evening as the likely severe weather event evolves.

Storms will continue moving eastward late Tuesday afternoon/evening; however, less instability will be in place and shear becomes less favorable, thus severe threat becomes more limited across the Lower Susquehanna Valley. Precipitation exits quickly and becomes more upslope/lake- enhanced rain showers in the wake of the cold front Tuesday night into early Wednesday morning. Storm total rainfall amounts will be generally less than 0.25" southeast of the I-99/I-81 corridor and perhaps exceeding 1" in parts of northwest PA that receive multiple rounds of storms.

LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
The cold front becomes quasi-stationary to the south of the MD Line early Wednesday night then pivots northward as a warm front across western PA on Thursday as a sfc low tracks from near Chicago into Lower MI by 02/00Z. Expect shower activity to ramp up particularly in the western/northwestern portions of the CWA through Thursday night near the intersection of the advancing warm front and increasing moisture transport and theta-e advection via relatively strong SSW 850mb LLJ and IVT.
Thursday night looks very mild in CPA for the first night of May 2025 with min temps 55-65F or +15 to +25 degrees above climo.

Scattered convection is likely to accompany the trailing cold front on Friday, followed by another potential round of showers Friday night into Saturday associated with the parent 500mb trough/cool temps aloft rotating through the region. There is a broad model consensus in a cooling trend Friday night into the first weekend of May with 24hr min/maxT deltas running 5 to 10 degrees lower vs. the previous night/day. That said, frost risk appears to be confined to the northern tier AM Sunday where the growing season is not active.

High confidence in a much nicer end to the first weekend of May as high pressure builds over the area into early next week.
Expect milder temperatures and pleasant, rain-free conditions Sunday and Monday with highs moderating into the 65-75F range.

AVIATION /19Z MONDAY THROUGH SATURDAY/
Little material change for the 18Z TAF cycle.

Earlier 15Z update introduced several hours of marginal LLWS late tonight and early Tuesday at all airfields as the south- southwesterly flow (above a mainly decoupled near surface layer with a light south wind) freshens to 25 to 30 kts in a layer between about 12-20 kft AGL.

High pressure across the region will (100% confidence) provide light and variable to light south winds and clear skies through about 29/06Z, followed by bkn-ovc high end MVFR to low end VFR strato cu clouds.

A dual layer of clouds (expanding cu field, topped by cirrus)
will move into western Pennsylvania ahead of showers/thunderstorms Tuesday afternoon; however, ceilings will remain primarily above 20,000ft AGL.

Tue...PM showers and possibly a few thunderstorms with restrictions possible. Brief gusty winds across W PA.

Wed...A few lingering showers across primarily SW PA.

Thu...Showers/t-storms return areawide, restrictions possible.

Fri...Showers with restrictions possible.

CTP WATCHES/WARNINGS/ADVISORIES
None.