Sunrise 5:19 AM   Sunset 8:04 PM Moonrise 11:08 AM   Moonset 1:45 AM

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FXUS61 KGYX 141020 AFDGYX

Area Forecast Discussion National Weather Service Gray ME 620 AM EDT Tue May 14 2024

SYNOPSIS
A quick round of showers crosses the area this morning with much warmer air arriving across southern NH and far southwestern ME for the day today. A cold front will then drop towards the region bring the chance for showers and thunderstorms this afternoon and evening. A stalled frontal boundary will result in unsettled weather for the middle and latter portions of the week with temperatures remaining seasonable for mid May.

NEAR TERM /TODAY AND TONIGHT/
620 AM Update...Minor tweaks to PoP/Wx to better capture the showers crossing into western ME.

Previous...

An area of showers currently across New Hampshire will steadily push east through this morning, bringing some measurable rain for portions the area but nothing significant. Amounts across central and northern areas may amount to a tenth to a quarter of an inch with up to a few hundredths for areas to the south.

Once this batch of showers moves out of the area, mostly dry conditions will prevail into this afternoon with partly sunny skies and warm temperatures before an approaching cold front brings increasing chances for showers and storms into this evening.

CAMs are in pretty good agreement focusing initiation across northern areas sometime mid-late afternoon with activity spreading southward into this evening. The warm temperatures and cooler temps aloft will provide enough instability to support thunderstorms, especially across northern and central NH over into the western Maine mountains and foothills, and a few of these could be strong with gusty winds and small hail. In addition to this threat, the mean flow is roughly parallel to the orientation of the convection in what some of the CAMs are depicting, particularly the HRRR and NAMnest. Although the location is uncertain, there is a signal that this could result in heavy rainfall persisting over some areas which may cause some hydro issues.

Farther south, CAMs are not showing much in the way of development, but with these very warm temps, development of isolated-scattered showers along with a couple of storms doesn't seem out of the question.

Central NH and southwest ME are expected to get well into the 70s for highs with southern NH closer to 80 degrees as a warm front slowly advances eastward. Farther east it will be cooler where winds will also be onshore, keeping temperatures in the 60s.

Convection is expected to linger into this evening, especially for central and northern areas, but potential for thunderstorms will steadily wane as instability is lost. Short-range guidance indicates most showers will then dissipate by midnight to 2am, but with the frontal boundary lingering nearby, can't rule out a few additional showers overnight. The main concern then becomes the potential for fog to develop, especially over areas that receive rain, and I wouldn't be surprised for some of it to be locally dense with light winds and dewpoints in the 50s.

SHORT TERM /WEDNESDAY/
Mostly cloudy skies are expected Wednesday with the frontal boundary stalling across the area. More than sufficient moisture will still be present, and another wave of low pressure riding along the frontal boundary will bring more showers to the area with perhaps a storm or two. Precipitable water is progged to be around 1.25", which is quite high for this time of year, so will have to watch for heavy rainfall potential once again. CAMs and global models are focusing in on central/northern NH along with areas from the foothills northward in western ME, which could be some of the same areas that receive heavy rainfall this afternoon. Have taken more of a consensus approach to high temperatures with clouds expected to limit temps to the 60s, but southern NH may still reach the lower 70s.

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
A slow moving cut off low pressure system tracks through the Mid Atlantic and offshore from Wednesday through Saturday before dissipating. Another slow moving low pressure system will take a similar track south of New England this weekend.

Details...

Overall the forecast over the last couple of days has trended toward warmer and a longer duration of unsettled conditions. So Thursday doesn't look quite as wet as they had, but Friday and Saturday now look to continue the chances for showers.

Cut off low pressure systems are notoriously tricky for both the models and forecasters to discern. With these being the main drivers of our forecast this week, it's worth noting that further changes are likely as well in the coming days. The cold front approaching from the north looks to be trending a little slower, and not making as much southward progress. This allows warmer temperatures into Thursday as the marine air is delayed by at least a couple of days. At the same time, the cut off low looks to be tracking more slowly. This causes the forecast to be quite similar for Thursday through at least Saturday with times of showers.

At least scattered showers are expected Thursday through Saturday. POPs on these days are likely to increase in some spots as we get closer in time and certain areas become more highlighted as seeing a better chance for rain. Overall, the best chance for seeing the most frequent showers looks to be across interior areas and the higher terrain. As for temperatures, highs looks to generally warm into the 60s and 70s each day, with the warmest readings found across western locations, and generally cooler toward the coastline.

As we get into next weekend, the next system will be following closely behind the first one. This likely increases chances for showers further during the day on Saturday and Sunday. It also looks to bring cooler temperatures, as easterly flow brings in cooler and damp maritime air. As mentioned, this forecast has been volatile over the last couple of days as the cut off low regime continues. This weekend's forecast is subject to change, but that's the way it looks to be trending at this point. Over the last week or so, the trend has generally been toward warmer and less wet conditions as we get closer in time, but it's too early to know at this point if that trend will continue this weekend.



AVIATION /08Z TUESDAY THROUGH SATURDAY/
Short Term...Brief restrictions are possible with showers this morning with mostly VFR well into this afternoon. A slow-moving cold front will then provide focus for additional showers this afternoon and evening, and thunderstorms may occur as well. IFR restrictions and gusty wind could accompany showers and storms with the higher potential for these impacts toward HIE, LEB, and CON. There is lesser confidence elsewhere. Showers and storms will diminish in coverage through this evening with a low chance of additional precip overnight tonight. However, low ceilings and fog are expected, especially in areas that receive rain. Additional showers are possible on Wednesday as the cold front will be stalled across the region with highest shower coverage generally north of a LEB- LEW-AUG line.

Long Term...Generally VFR conditions are expected more often than not from Thursday through Saturday, but periods of MVFR conditions with showers are likely during this time period. By next weekend, longer periods of MVFR to possibly IFR look likely with more showers and some marine fog possible.

MARINE
Short Term...Southerly winds continue to increase today as a cold front slowly approaches. Gusts are expected to remain shy of SCA criteria, although a brief period of 20-25 kt is possible over the outer waters late this afternoon or early evening. The front then stalls to the northwest of the water through Wednesday with a south to southwest flow continuing but still remaining below SCA levels.

Long Term...A slow moving low pressure system tracks south of the waters from Wednesday night through Saturday. Seas begin to build by Friday, with SCA conditions possible by late in the week and this weekend.

GYX WATCHES/WARNINGS/ADVISORIES
ME...None.
NH...None.
MARINE...None.

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