Marine Weather and Tide Forecast for Whitaker, PA

NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:

- Dry and warm conditions expected today ---------------------------------------------------------------

Quiet and dry weather expected today as ridging builds over the region. Strong warm advection aloft will keep a cap on convection. This morning's Pittsburgh sounding has a convective temperature of only 80F, however, upstream in Wilmington, OH, 500mb temperatures are much warmer (6C warmer), and this will out a lid on updrafts. Observed soundings suggest daytime highs right around what is currently forecast (mid 80s to 90F), so no changes will be made to the ongoing forecast. Despite relatively clear skies and light wind, overnight lows will bottom out around 10 degrees above normal for this time of year.

SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/
KEY MESSAGES:

- Extreme heat threat ramping and peaking Monday and Tuesday.
- Potential record high and low temperatures.
- Extreme Heat Warning in effect Sunday - Wednesday.
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The weather story beginning on Sunday and continuing through next week is a prolonged period of dangerous, extreme heat; an Extreme Heat Warning is in effect for Pittsburgh metro and surrounding counties and a Heat Advisory is in effect elsewhere beginning Sunday.

The first day of significant heat occurs on Sunday with height rises of 4-6 dam as we're engulfed by the 596 dam contour on all ensembles resulting in highs likely to top 90 degrees across most of the area.
Heat indices will reach 100-105F, highest in the valleys and urban areas. Plenty of subsidence will keep the area dry.

Ensembles exhibit uniform certainty on a strong upper ridge building across the eastern CONUS with a 100+% chance of 500 mb heights >595 dam; probability suggests heights sit between 596-598 dam Sunday- Tuesday with some regression beginning on Wednesday. Ensemble mean 850 mb temperatures soar to 20-22C. NBM probability for highs >90F is remarkably high at 95-100% Sunday through Wednesday, but of note is that NBM probabilities and statistical distribution in a high- predictability can often be artificially inflated when post- processing is applied to a small spread in the distribution like we have in this case for MaxTs. What this means is that the more likely high temperature might fall a degree or two below the NBM post- processed mean (perhaps the 90-95F range as opposed to widespread 95F+), especially with forecast dew points in the mid 70s. Last year's period of extreme heat showed that the NBM handled the dew points pretty well while overdoing the MaxTs by a couple degrees, so it's most likely that we find a middle ground with low to mid 90s temps and low 70s dew points. Either way, heat indices are very likely to reach the 100-105F range for several consecutive days.
Compounding the effects of extreme daytime heat will be little relief at night as probability for lows >70F is 80-90+% Sunday- Wednesday nights.

Record lows and highs may be in jeopardy... see the climate section for more. In preparation, it is a good idea to find out more about your local cooling shelters and consider altering outdoor plans to at least outside of the afternoon peak heating window.

LONG TERM /WEDNESDAY THROUGH SATURDAY/
KEY MESSAGES:

- Low predictability showers and storms possible Wednesday and Thursday.
- Lower confidence in how long the extreme heat hangs around.
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By mid-week, we may re-introduce severe weather and flash flooding again as the heat begins to subside, though by that point the lower predictability convective development will play a large role in whether or not heat headlines need extended beyond Wednesday. This looks possible Wednesday but more likely Thursday and Friday as some subtleties in the flow/regression of the ridge allow for convective potential riding atop it. Ensemble forecast soundings indicate that plenty of DCAPE (750-1200 J/kg) should be available with weak effective shear (10-15 kt) underneath the ridge and increasing PWAT values to 1.5-1.8" all supportive of slow moving storms with heavy rain and downburst potential. Should these become more widespread and higher confidence, MaxTs/AppTs on Thursday and Friday may not be as high as currently forecast. NCAR's medium-range machine learning guidance has increased the probability of severe weather to 30-40% over our region for the Thursday/Friday timeframe.

Something to monitor in the coming days: With the focus for strong to severe storms remaining at the US/Canada border, the potential for wildfires may develop. Depending on how the upper- level pattern evolves, this could lead to degraded air quality in the long term. However, this outlook is contingent on the development of wildfires sparked by lightning in heavily forest areas to our north.

AVIATION /18Z SATURDAY THROUGH THURSDAY/
VFR is expected through the TAF period as ridging builds in across the region. Winds will remain relatively light and southwesterly with sfc high pressure centered southwest of the region.

Outlook...
VFR is expected through Tuesday under a strong ridge. Potential for restrictions and showers/thunderstorms return Wednesday as the ridge begins to drift south.

CLIMATE
Daily record high maximum (left) and daily record high minimum (right)
temperatures will be in jeopardy starting this coming Sunday:

Sunday June 22nd Pittsburgh, PA: 98F (1988) 75F (1988)
Zanesville, OH: 99F (1988) 71F (1997)
Morgantown, WV: 96F (1923,1988) 73F (1988)
Dubois, PA: 92F (2024) 69F (2024)
Wheeling, WV: 95F (1923, 2024) 72F (2011)
New Philadelphia, OH: 97F (1988) 71F (1997)

Monday June 23rd Pittsburgh, PA: 95F (1894) 76F (1888)
Zanesville, OH: 96F (1899) 70F (1975)
Morgantown, WV: 95F (1899) 71F (1957)
Dubois, PA: 88F (1966) 66F (2017)
Wheeling, WV: 94F (1948) 69F (2013)
New Philadelphia, OH: 97F (1988) 72F (1948)

Tuesday June 24th Pittsburgh, PA: 96F (1882) 72F (1884)
Zanesville, OH: 98F (1930) 73F (1937)
Morgantown, WV: 94F (1921, 1949) 76F (1924)
Dubois, PA: 88F (1966) 67F (2013)
Wheeling, WV: 98F (1933, 1943) 73F (1908)
New Philadelphia, OH: 94F (1964) 70F (1975)

Wednesday June 25th Pittsburgh, PA: 98F (1988) 75F (1952)
Zanesville, OH: 101F (1988) 72F (1952)
Morgantown, WV: 94F (1921, 1952, 1988) 74F (1952)
Dubois, PA: 91F (1966) 67F (2000)
Wheeling, WV: 97F (1943) 75F (1952)
New Philadelphia, OH: 92F (1966, 2002, 2005) 68F (2013)

Thursday June 26th Pittsburgh, PA: 95F (1966) 75F (1952)
Zanesville, OH: 97F (1952) 73F (1952)
Morgantown, WV: 96F (1952) 74F (1952)
Dubois, PA: 91F (1966) 66F (2000)
Wheeling, WV: 96F (1943, 1952) 73F (1952)
New Philadelphia, OH: 99F (1988) 71F (2022)

PBZ WATCHES/WARNINGS/ADVISORIES
PA...Heat Advisory from 11 AM Sunday to 8 PM EDT Wednesday for PAZ007>009-013-015-016-022-031-074-076>078.
Extreme Heat Warning from 11 AM Sunday to 8 PM EDT Wednesday for PAZ014-020-021-029-073-075.
OH...Heat Advisory from 11 AM Sunday to 8 PM EDT Wednesday for OHZ039>041-048>050-057>059-068-069.
WV...Heat Advisory from 11 AM Sunday to 8 PM EDT Wednesday for WVZ001>004-012-021-509>513.