Sunrise 6:06 AM   Sunset 7:57 PM Moonrise 10:13 PM   Moonset 6:17 AM

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FXUS61 KCTP 260942 AFDCTP

Area Forecast Discussion National Weather Service State College PA 542 AM EDT Fri Apr 26 2024

SYNOPSIS
High pressure near Ottawa Canada will provide a relatively cool, east to southeasterly flow of air today, but conditions will be dry.

A warm front will drift northeast across the Commonwealth Saturday but moisture associated with it will be limited and showers occurring along and ahead of this boundary will be relatively light.

Daytime high temperatures will jump by around 20 degrees on Sunday with just a few, scattered showers or thunderstorms across the northern Mountains of the state.

NEAR TERM /UNTIL 6 PM THIS EVENING/
A very weak, surface trough extended from Southwestern PA into the Central Mtns. This boundary will combine with limited low level moisture being transported off the Western Atlantic to bring some shallow morning stratus/stratocu clouds over the Laurel Highlands and South Central Pennsylvania.

Vertical Mixing reaching up to 4-5 kft agl will greatly dissolve this cloud layer leaving just scattered, cumulus pancakus for the late morning and afternoon hours.

Low humidity once again today will create excellent vsby as layer PWAT values are only around 0.3 of an inch.

Temps will be 3-6 deg warmer than Thursday. Look for high in the upper 50s across the Northern and Western Mtns and low 60s in the Central and Southern Valleys.

SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/
Showers along a warm front will spread into the Western Alleghenies very late tonight or more likely early-mid morning Saturday - based on the latest operational model/HRRR consensus.

PWATs will surge from west to east very late tonight and Saturday, reaching 1-1.2 inches, along and in the wake of a warm front. Late Saturday morning through mid afternoon Saturday holds the greatest chance for showers. QPF will be quite light, ranging from 1-2 tenths of an inch across the Western Mtns to between 0.05 and 0.10 across the Central Mtns and just a few hundredths of an inch expected across the Southeast.

Min temps tonight will be 6-12F milder than early this Friday.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/
Lingering clouds with just some patchy drizzle and light fog are possible later Sat night. Mins Sat night/Sunday morning will climb by another 7-9 deg F compared to readings early Saturday.

Brightening skies and markedly warmer conditions appear likely Sunday, as the warm front lifts north of the region. However, ensemble plumes indicate scattered PM convection is possible, especially over the N Mtns, where progged pwats are highest and temps aloft coolest.

Fair and unseasonably warm weather is likely Monday, as anomalous upper level ridge crests over the state. Mean 850mb temps near 15C supports max temps in the low to mid 80s. All medium range guidance points to a good chance of PM convection Tuesday associated with the passage of a mid level shortwave.

Diverging model solutions and greater uncertainty then creep into the forecast the second half of next week. Upper level ridging and above average temperatures look very likely.
However, timing differences exist with regard to an upstream trough and associated cold front late next week. Expect a widespread round of convection to accompany the front either Thu PM or Friday.

AVIATION /09Z FRIDAY THROUGH TUESDAY/
VFR conditions are expected to continue across most of the area tonight under high pressure. The exception will be across southern portions of Central PA where lingering low level moisture could lead to some low cloud or fog formation. An area of low clouds currently to the south of the area are beginning to expand northward and will likely approach JST and AOO by 08Z.
Most guidance suggests that those airfields will remain VFR through the night, but the HRRR/SREF show a 20-40% chance of MVFR or potentially IFR ceilings developing at JST into the morning. Confidence in this outcome occurring is low, though.

Any clouds and fog that form overnight will gradually decrease in coverage in the morning, though clouds could stick around slightly longer across the Laurel Highlands with light upslope flow. Otherwise, mainly clear skies are expected area-wide. An approaching warm front will lead to an increase in high clouds after 00Z Friday.

Outlook...

Sat...Scattered shra. IFR cigs possible Central Mtns.

Sun...AM low cigs possible, mainly N Mtns. Isold PM tsra possible.

Mon...No sig wx expected.

Tue...Sct PM tsra impacts possible.

FIRE WEATHER
Fuel moisture may fall below 10% over the next two days.
Return flow around departing high pressure on Friday may slightly increase the potential for spread on Friday afternoon, mainly across the higher terrain to the NW of a KCBE to KAOO and KUNV line where SE wind gusts into the mid and upper teens are possible for about 3 hours this afternoon.

MinRH this afternoon (Fri) is forecast to be mainly between 30 and 35 percent, though the Laurel Highlands will only dip to between 40 and 45 percent.

An approaching warm front will result in a cloudy and relatively cool Saturday, with a chance of showers accompanying the passage of a weakening, south to southwesterly low level jet. Weak large scale forcing under an upper level ridge should result in minimal rainfall. Most likely rainfall by Sat PM based on ensemble plumes ranges from around 0.2 inches over the N Mtns, to just a few hundreths over the southeast counties.

Increasing low level moisture/dewpoints along with some rain will limit fire weather concerns this weekend.

CTP WATCHES/WARNINGS/ADVISORIES
Freeze Warning until 8 AM EDT this morning for PAZ004-005-010- 011-017-018.
Frost Advisory until 8 AM EDT this morning for PAZ019-024>028- 045-046-049>053-056-057-059-063-065-066.

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Market Street Bridge
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Fri -- 03:36 AM EDT     6.49 feet High Tide
Fri -- 06:06 AM EDT     Sunrise
Fri -- 07:17 AM EDT     Moonset
Fri -- 11:19 AM EDT     0.49 feet Low Tide
Fri -- 04:07 PM EDT     5.35 feet High Tide
Fri -- 07:50 PM EDT     Sunset
Fri -- 11:05 PM EDT     Moonrise
Fri -- 11:16 PM EDT     0.81 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Market Street Bridge, Schuylkill River, Pennsylvania, Tide feet

Norwood City
Click for Map
Fri -- 03:23 AM EDT     6.16 feet High Tide
Fri -- 06:07 AM EDT     Sunrise
Fri -- 07:18 AM EDT     Moonset
Fri -- 10:53 AM EDT     0.46 feet Low Tide
Fri -- 03:54 PM EDT     5.07 feet High Tide
Fri -- 07:51 PM EDT     Sunset
Fri -- 10:50 PM EDT     0.76 feet Low Tide
Fri -- 11:05 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION

Norwood City, Darby Creek, Pennsylvania, Tide feet

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