Lancaster, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

422
FXUS61 KCTP 071836
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
236 PM EDT Sun Jun 7 2026

.WHAT HAS CHANGED...
* Subtracted a deg or two from maxes M-W, but kept continuity
  for R-F to keep message the same for high heat and humidity.

&&

.KEY MESSAGES...
1) Fog possible in sheltered valleys, mainly north, overnight
as temperatures cool off into the 50s.

2) Low RHs

3) Warmth surges again later this week with dangerous heat
possible Thursday and Friday.

&&

.DISCUSSION...
KEY MESSAGE 1: Fog possible in sheltered valleys, mainly north,
overnight as temperatures cool off into the 50s.

Diurnal cu should dissipate as the sun goes away. Selling tix to
the battle between the dryness of the airmass vs cooling to the
local dewpoints tonight to determine how much fog can form.
Current odds (62.7%) are that fog will form in the deepest
river valleys - mainly of the north - tonight. But, the coverage
will be rather limited. While the airmass is dry, the temps
should be dipping to and perhaps below the crossover temps (mid-
aftn dewpoints) in the lower elevations of the Allegheny
Plateau. Otherwise mainly clear sky and light NE wind, if any,
will make for a window-open night.

--------------------------------------------------------

KEY MESSAGE 2: Low RHs

RH will dip into the upper 20s and 30s Mon, and 30s over the
east on Tues. Paired with relatively light wind and the greened-
up landscape, though, it should yield no elevated risk for
rapid wildfire spread.

--------------------------------------------------------

KEY MESSAGE 3: Warmth surges again later this week with
dangerous heat possible Thursday and Friday.

While the NBM max temps have inched lower by 1-4F for the next
couple of days, the latter half of the week still looks hot.
90s should be widespread Thurs and Fri. The elevations of the
Alleghenies will be the coolest spots, but the valleys there
could also get to 90F. Heat Index/ApparentT values remain
virtually unchanged for those two days.

The new/cooler temps T-W are likely due to the raised cloud
cover and higher chc of precip vs prev guidance. Categorical
(80%+) PoPs appear Tues night over the west as moisture
increases and sct TSRA are expected. These shouldn`t get too far
to the east, perhaps staying W of UNV/AOO. Wed will hold
widespread SHRA/TSRA over the bulk of the CWA as the upper ridge
weakens and shortwaves (old MCSs) crest the ridge and meet up
with the increasing moisture.

Only slight relief arrives Sat, but temps remain very warm/hot.
The 6-10 and 8-14 day outlooks are for continued above normal
temps (and precip). Above normal precip would help out the areas
that continue to be in drought.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Lingering low-level moisture (Td in the 50s-60s) behind this
morning`s frontal passage will maintain a diurnally driven
cumulus field through this evening. Otherwise, a high pressure
will slide down the Adirondacks tonight, bringing a chance for
patchy fog across the Northern Tier (KBFD) and East-Central
Mountains (KIPT/KUNV/KAOO) where clear skies and light winds
will be most favorable for radiative fog. Using a GLAMP/HREF
blend, flight restrictions are possible (30-50% chance) at KBFD,
with lower probabilities (20-30% chance) elsewhere at this
time, although KUNV is slightly favored for patchy mist/fog on
current model guidance vs. KIPT/KAOO.

This high pressure will also bring a backdoor cold front to our
easternmost terminals (KIPT/KMDT/KLNS) Monday morning
(09Z-12Z). The GLAMP highlights a low chance (20% chance) of
MVFR with the clouds behind this front, though uncertainty
regarding sky cover precludes ceiling restrictions in TAF at
this time. Diurnal VFR cumulus field redevelops across much of
central Pennsylvania during the daytime Monday as the front
diffuses & return southerly flow develops on the western
periphery of the high pressure.

Outlook...

Mon-Tue...VFR favored outside of isolated morning fog.
Restrictions possible in -SHRA/-TSRA early Sun & again late Tue.

Wed-Fri...Restrictions possible in -SHRA/-TSRA.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

WHAT HAS CHANGED...Dangelo
KEY MESSAGES...Dangelo/Colbert
DISCUSSION...Dangelo/Colbert
AVIATION...Teare