Marine Weather and Tide Forecast for Felton, PA

NEAR TERM /UNTIL 6 PM THIS EVENING/
Low clouds have spread across all of the northern mtns. Chances are that the frost had already formed where the clouds have moved in. If they had moved in any faster, that might have negated frost. The layer of moisture is thin, so they should go away as we mix/heat. Still, they will take a couple of hours to break up esp in the NE where theclouds are the thickest and they are stuck in the middle of the cloud patch. Otherwise, the forecast stands up well. Only minor tweaks to be made.

Prev...
Fog forming up in the NW where the temps are bottoming out right around fcst numbers. Low clouds are moving down from the Finger Lakes and will make it more cloudy this morning than earlier expectations, and could end up stopping/melting the frost where they do invade, generally along the NY border. After the frosty start, temps should rise into the 60s, and perhaps 70F in the srn valleys/metro areas. Precip will hold off until tonight as the minor upper ridge with it's axis just to the west holds on for the daylight and evening.

SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/
Most of the chatter this morning is on QPF and the threat for excessive rainfall and flooding. See Hydro section for details.

Sfc low over the Midwest moves quickly into the upper OH Valley tonight as a warm front nears. The front is likely to hang up just to the S/W of the CWA through Wed evening/night. Cooler temps on Wed should limit deep convection and chc TS except in the far W, esp SW, where a few TS may clip the CWA The complex system of fronts will serve to focus rainfall over the CWA through the entire period. Temps will dip into the M40s NE and L50s SE tonight. But, they won't rise much at all on Wed. Maxes may only be 5F higher than morning temps. Limited diurnal ranges last into Fri with maxes about 15-20F below normals.

LONG TERM /FRIDAY THROUGH MONDAY/
Northwesterly flow in the wake of the departing low pressure system will allow for cooler than average temperatures to take hold for the end of the week and throughout the Memorial Day weekend. A secondary area of surface low pressure is progged by model guidance to form off the Mid-Atlantic Coast late Thursday/early Friday will quickly pull northeast of the area, allowing for conditions to begin to dry out late Friday night.
Any lingering rainfall on Friday is expected to generally light and taper off southwest-to-northeast.

Enhanced northwesterly flow Saturday through Monday will bring a return to shower chances with upslope and lake-enhanced showers; however, as low-level flow begins to decrease later in the evening, gradually will see shower activity shut off with lingering precipitation generally expected to be light.

AVIATION /12Z TUESDAY THROUGH SATURDAY/
VFR conditions and, apart from a few high clouds, skies will be mainly clear overnight and through Tuesday morning across the airspace. Can not completely rule out some patchy fog developing in the deeper river valleys of west- central PA overnight, but the HRRR suggests that the chance for any impacts at TAF sites is less than 20%.

Cloud cover begins to increase Tuesday afternoon ahead of an approaching low pressure system that will bring the next chance for rain to the region. Any restrictions look to hold off until after 00Z Wednesday.

Outlook...

late Tue PM-Fri...Ocnl SHRA/TSRA.

Sat...Still a chance of a shower.

HYDROLOGY
The first wave of precip tonight should not create any flooding issues. But, the threat of thunder over the west and the constant focus of moisture and rainfall over the CWA thru the next few days will increase the threat for flooding. QPF is generally a gradual build up of 0.25-0.50" per 12 hrs on average. But, some periods, specifically Wed and Wed night, will have a bit higher rates. The main concerns for flooding potential are in the W/SW (Somerset,Bedford and up to Clearfield). FFGs start out >1.75"/3hrs in the SW where the highest precip should end up over the next few days. Storm total amounts there will be in the 2-3" range for those western locations already mentioned, and 1-2" for the balance of the CWA Wet ground and actually lower FFG is seen over places from Perry Co north and east. The lowest guidance is over Tioga and Sullivan Cos. 3 hr FFG is between 1-1.5". Thankfully, those numbers are just about where the storm totals are for much of that area.

The possibility of flood watches were discussed this AM around the region with all concerned forecast offices and WPC. The consensus is to hold off one more cycle, as rainfall doesn't begin for another 18-24 hrs in our SWrn Cos. WPC ERO has much of the area is the MRGL risk, and the SW in SLGT risk for DY2.
That seems very reasonable. But, the threat is still developing.
Again, without deep convection over the balance of the area, it might be a tough thing to push even the creeks out of their banks. Again, the most likely place for a watch is the W/SW, followed by the middle of the CWA The most concerning time frame is the Wed-Wed night period. The precip should be lighter and more spotty on Thurs.

CTP WATCHES/WARNINGS/ADVISORIES
Frost Advisory until 8 AM EDT this morning for PAZ004>006- 010>012-017-018-037-041-042.