textproduct: State College

WHAT HAS CHANGED

* Freeze Warning/Frost Advisory issued for tonight-Tuesday AM

KEY MESSAGES

1) Freeze and frost conditions could kill crops and other sensitive vegetation tonight into early Tuesday morning

2) Cool/Wet weather for midweek with limited/light rain amounts

3) Early May chilly pattern projected to break down this weekend triggering a significant summerlike warmup into next week

DISCUSSION

KEY MESSAGE 1: Freeze and frost conditions could kill crops and other sensitive vegetation tonight into early Tuesday morning

"Self destruct" cu field fades into tonight with low pwat air and clear/calm synoptic conditions setting up a very chilly and frosty night. Confidence is high for frost/freeze in the advisory and warning areas and could even see patchy frost in the outlying rural areas in the LSV. Guidance hints at some pesky cloud cover over southwest PA that could hinder frost/freeze in parts of the Laurel Highlands, but with any breaks and elevation we still felt headlines were needed.

KEY MESSAGE 2: Cool/Wet weather for midweek with limited/light rain amounts

A seasonably strong upper level trough will carve out over Great Lakes Tue-Thu and eventually close off over New England by the end of the week. The upper trough and its associated sfc low and trailing cold front will bring wet weather to CPA for midweek with periods of rain/showers and perhaps a few t-storms. Total rainfall amounts through 00Z Friday are on the light side and less than 0.50 inch in most locations. Look for steadier light rain Tuesday night-Wednesday to become more showery by Thursday before conditions start to dry out Thursday night- Friday.

KEY MESSAGE 3: Early May chilly pattern projected to break down this weekend triggering a significant summerlike warmup into next week

Guidance signals a significant warmup on the horizon as the upper level trough ejects eastward into the northern Atlantic and mean jet stream flow lifts northward. This large scale pattern shift should deliver a significant warm surge into the back half (2H) of May with summerlike temperatures forecast by early next week. There is even some potential heatrisk considerations (after a rather cool stretch) with current max temps in the 80-90F range on Monday. Rainfall should remain light/limited with low chances for sct showers or isolated t-storms.

AVIATION /18Z MONDAY THROUGH SATURDAY/

18z update... Fairly high confidence (80-90%) in VFR/unrestricted conditions for the central PA TAF sites through Tuesday.

Although probabilities are small (on the order of 10-20%), if radiational cooling conditions really maximize overnight across the northern PA river valleys, patchy fog in the vicinity of KBFD is not completely out of the question. At this time, low probabilities preclude such a mention in the terminal forecast.

W-NW surface winds this afternoon of 8-10 kt (occasionally gusty) will quickly diminish overnight and early Tuesday.

Outlook...

Wed...Restrictions possible with showers.

Thu...Lingering clouds and showers.

Fri...VFR likely.

Sat...At least brief restrictions may develop by afternoon, with potential scattered shower activity.

CLIMATE

State College COOP (STCP1) recorded the 20th coldest first 10 days of May going back to 1893 (133 years). The average temperature was 51.1 degrees and tied 1995 and 1893 as the 20th coldest on record.

CTP WATCHES/WARNINGS/ADVISORIES

Freeze Warning from midnight tonight to 8 AM EDT Tuesday for PAZ004>006-010>012-017-018-024-033-037-041-042. Frost Advisory from midnight tonight to 8 AM EDT Tuesday for PAZ019-025>028-034-035-045-046-049>053-058.