Area Forecast Discussion
Issued by NWS State College, PA

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113 FXUS61 KCTP 191837 AFDCTP Area Forecast Discussion National Weather Service State College PA 237 PM EDT Sat May 19 2018 .SYNOPSIS...
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A weak cold front will pass through the area overnight, leading to drier weather for Sunday. The region will stay on the northern periphery of the subtropical ridge through early next week meaning it will remain unsettled.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Steady rain has moved off to the NE of the forecast area, with just scattered showers remaining mainly over eastern areas. Satellite shows all but a narrow corridor from Somerset up into the NW mountains remaining locked in with low clouds. Over western areas where the sun is out, some modest instability is kicking off new showers and thunderstorms over far SWRN PA. Models suggest these could affect my far western stripe of zones into the evening hours. The deterministic HRRR shows convection moving through my western zones into central PA throughout the late afternoon and evening, keeping the activity quite disorganized. The various flavors of the SPC HREF similarly show mainly disorganized showers moving into our area into the evening, but showing more of a trend toward fading after sundown. For the forecast I tried to show the best chance for a shower/storm over western areas, with the chances diminishing over central and eastern areas. A weak cold front will enter the region around midnight, and should be clearing my SERN zones shortly after sunrise. Significant drying will probably hold off until during the day Sunday. With the continuation of mainly overcast skies and light winds, the overnight lows will not drop off too much, remaining generally in the 50s to mid 60s.
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&& .SHORT TERM /SUNDAY/...
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Sunday will start off rather murky once again as the weak cold front slides through our SERN zones. The wind will turn out of the west and eventually NW and freshen to 10-15 mph by late morning and afternoon. The best chance for a shower will likely be over eastern areas and during the first part of the morning before we see some drier air filtering in from the west. The afternoon should be quite pleasant with a mix of sun and clouds and temperatures recovering closer to what they should be in mid May, around 70 over the north to around 80 in the south.
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&& .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... After a showery overnight Sat night, Sunday will turn drier, especially for the afternoon as the exiting upper trough/sfc front leads to rising heights aloft. The timing of the sfc cold fropa is during the mid morning hours over the west, late morning across much of the Susq Valley, and during the late morning/afternoon hours in the Southeast. After being suppressed to our south early next week, the chances for showers will increase once again Monday as moisture on the northern periphery of the subtropical ridge creeps back into the region. I used blended MOS POPs leading to a mention of mainly afternoon showers/thunderstorms. Then as if from the department of redundancy department, the showery forecast sticks around for Tuesday before drier air makes a push for Wednesday. I actually cut back on the blended MOS POPs for Wednesday leaning closer to the GEFS idea of drying behind a weak cold front. From there it looks like the period form Wednesday afternoon through Friday morning will feature some rare rain free conditions before the chance for a pop up shower or storm becomes possible before the day is over Friday. Rainfall to date has already exceeded monthly normals at Harrisburg and Williamsport and is on a pace to be wetter than a normal May at Altoona, Johnstown, Bradford and State College. It looks to stay unsettled at least into early next week. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/...
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Widespread MVFR/IFR will continue with only slow improvement over western sections as partial sunshine leads to some mixing out of the low clouds. JST has broken out and is VFR as of early afternoon, but the SE flow overnight should drive the sub VFR ceilings back in shortly after sundown. Sunshine has led to some modest instability over western areas and a few thunderstorms are possible over the western 1/3 of the airspace as we move into the evening. Scattered showers are likely to persist into the overnight as a cold front pushes through the area. Model guidance is indicating a wind shift to the west by Sunday morning which should spell improvement at airfields east of the Alleghenies. Expect Sunday to start off with widespread MVFR/IFR, but drier air promises to bring improving conditions by late morning into the afternoon. Outlook... Mon-Tue...Variable conditions with isolated/sct showers and Tstorms. Wed-Thu...AM Fog then mainly VFR/no sig wx.
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&& .CTP WATCHES/WARNINGS/ADVISORIES...
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None.
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&& $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...La Corte LONG TERM...La Corte/Lambert AVIATION...La Corte

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