textproduct: State College

WHAT HAS CHANGED

* Expanded Dense Fog Advisory (DFA) to the western Alleghenies and I-81 corridor in Lebanon and Schuylkill Counties * Lowered max temperature forecast for today

KEY MESSAGES

1) Areas of dense fog/low visibility could make driving conditions hazardous this morning

2) Periods of beneficial rainfall expected into the first weekend of March

3) Warmest temperatures since late Fall poised to arrive in the coming days

DISCUSSION

KEY MESSAGE 1: Areas of dense fog/low visibility could make driving conditions hazardous this morning

Low clouds and areas of dense fog will continue low visibility and locally hazardous driving conditions early this morning. DFA was expanded along the western Alleghenies (ridgetops) and I-81 corridor in Lebanon and Schuylkill Counties where road obs show minimum vis around 500ft with speed restriction btwn exits 138 and 89. SPS also issued for slippery spots and black ice over the Endless mtns where air/road temps are hovering around 32F. Expect a gradual improvement in visibility through midday with breaks of sun most likely over the northern tier by the afternoon.

KEY MESSAGE 2: Periods of beneficial rainfall expected into the first weekend of March

On the heels of one of the driest winter seasons on record, periods of beneficial rain are expected into the first weekend of March. Light rain lingers over the southern tier today before a more robust moisture surge returns widespread rain to CPA overnight through Thursday. QPF for Friday looks pretty light and spotty at this time, so bulk of total rainfall fcst in the 0.75-1.25" range is expected tonight and Thursday. The next best chance for rain would be Saturday-Saturday night with another probable dry stretch Sunday into next Monday.

KEY MESSAGE 3: Warmest temperatures since late Fall poised to arrive in the coming days

Persistent and amplified Southeast U.S./Atlantic centered upper ridging will promote a significant springtime warming trend into the second week of March. Fcst max and min temperatures will be 15-30 degrees above the historical average Sat-Wed and may challenge daily records.

CAD pattern looks to delay the ramp-up in springtime warmth to some extent on Friday, although fcst highs are still 15-25F above the historical average along the western periphery of the CWA. Saturday continues to signal as the the warmest day out of the next 5 as we manage to break into the warm sector.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

IFR/LIFR conditions will continue for all TAF sites into the morning with expansive low stratus and fog. VFR conditions will return to BFD and IPT by late morning as a brief shift to northwesterly flow aloft brings drier air overhead. Recent model runs have shown conditions improving to MVFR or possibly even VFR at UNV, MDT, and LNS for the afternoon, though confidence in this is low as some guidance keeps these sites solidly IFR through the entire TAF period.

The low clouds look to be more stubborn for JST and AOO, with those sites likely remaining IFR or LIFR through the day on Wednesday. The LAMP even keeps visibility below 1/2SM through 12Z Thursday, but this might be a little pessimistic.

Any improvements will be short-lived, with IFR conditions expected to return area-wide tonight as low clouds and fog expand once again.

Most of the region will be dry on Wednesday, but a few showers could move across southern PA during the afternoon. These would be most likely to impact JST and AOO, though they could reach as far east as MDT. Widespread rain returns to the region after 06Z Thursday.

Outlook...

Thu...Restrictions likely with widespread rain associated with a warm front.

Fri...Stationary front across the region. Restrictions possible, especially across central/eastern airfields.

Sat...Restrictions remain possible, especially in the north and east. VFR most likely from KJST south and west, where winds could get gusty in the warm sector. Afternoon/evening showers and thunderstorms likely with cold FROPA.

Sun...Trending towards VFR.

CTP WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until 9 AM EST this morning for PAZ004>006- 010-011-017-024-033-058-059.