Marine Weather and Tide Forecast for Felton, PA

KEY MESSAGES
1) A line of thunderstorms this afternoon and evening precedes unseasonably cool Thursday. Thunderstorms may contain gusty winds and small hail.

2) Significant summerlike warmup ramps into early next week with the highest temperatures of the year so far.

DISCUSSION
KEY MESSAGE 1: A line of thunderstorms this afternoon and evening precedes unseasonably cool Thursday. Thunderstorms may contain gusty winds and small hail.

A seasonably strong upper level trough will dig through the Great Lakes/Ohio Valley today and develop into a closed low over the northern Mid-Atlantic and southern New England region before ejecting to the northeast on Friday. The associated sfc low moving east from Lower Michigan toward northern New York will drag a trailing cold front across the Alleghenies this afternoon and evening. Steepening midlevel lapse rates, especially in north central and NW PA, will support convection with frequent lightning and mostly pea to dime size hail, although some of the strongest cells could contain quarter size hail. Sufficient (30-40kt) deep layer shear and steepening low level lapse rates support a marginal wind threat as well.

The HRRR/REFS show the primary frontal band exiting the eastern portion of the CWA after 14/03Z. If there is some clearing overnight (best chance from the Susq River eastward), moist low levels cloud result in patchy fog into early Thu AM. Plenty of clouds lingering across the western highlands should prohibit fog in that area.

Scattered showers linger into Thursday beneath the upper low.
Thursday will be the coldest day of the week. Max temps will be unseasonably cool and quite chilly for mid May with highs in the 45-60F range or 10 to 20 degrees below the historical average (frequent 20-25 mph wind gusts will only add to the chill).

Conditions will dry out on Friday with daytime highs rebounding +10-20 degrees vs. Thursday.

KEY MESSAGE 2: Significant summerlike warmup ramps into early next week with the highest temperatures of the year so far.

After a cool start to May, guidance continues to signal a significant warmup on the horizon for this weekend into early next week. This large scale pattern shift should deliver a rather sudden warm surge with max temps projected to reach well into the 80s and even lower 90s. Daily record highs may be challenged based on the current fcst Monday and Tuesday.

There may be some potential Heatrisk considerations looming for early next week. This stems not only with the forecast high temperatures, but also from an acclimation perspective especially after a rather cool stretch of weather during the first half of May. Probabilistic Heatrisk shows >50% odds for moderate or higher levels across south central PA with fcst heat index values starting to exceed 95F Monday and Tuesday.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/
Expect TSRA activity to pick up from NW to SE along and ahead of a cold front. BFD will see a glancing blow from a thunderstorm by 19z, with small hail and strong gusty winds possible especially just north of the airfield. TSRA will then be possible at JST, AOO, UNV, and IPT by late afternoon to early evening. Storms will be on a weakening trend as the arrive in MDT/LNS after 00z.

As the upper level low drops to the south tonight into Thursday, moisture will wrap around the low. This will result in low stratus and showers especially across the mountains. A brief window for clearing later tonight in the east may result in patchy fog along and east of the Susq River. Low stratus will result in cig restrictions in the western airfields all day Thursday, potentially dropping as low as LIFR at BFD and JST later tonight into early Thursday.

Conditions will improve later on Friday, as the low moves away from the area.

Outlook...

Thu...Lingering clouds and showers with restrictions north/west and improvement southeast.

Fri...VFR likely.

Sat-Mon...VFR is likely much of the time, although brief restrictions are possible with isolated afternoon/evening showers and thunderstorms.

CLIMATE
Record low temperature of 25 degrees was tied (1963) at Bradford yesterday.

CTP WATCHES/WARNINGS/ADVISORIES
None.