National Weather Service (2024)

Area Forecast Discussion
Issued by NWS Portland, ME

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-- Discussion containing changed information from previous version are highlighted. --452FXUS61 KGYX 141020AFDGYXArea Forecast DiscussionNational Weather Service Gray ME620 AM EDT Tue May 14 2024.SYNOPSIS...A quick round of showers crosses the area this morning withmuch warmer air arriving across southern NH and farsouthwestern ME for the day today. A cold front will then droptowards the region bring the chance for showers andthunderstorms this afternoon and evening. A stalled frontalboundary will result in unsettled weather for the middle andlatter portions of the week with temperatures remainingseasonable for mid May.&&.NEAR TERM /TODAY AND TONIGHT/...
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620 AM Update...Minor tweaks to PoP/Wx to better capture the showerscrossing into western ME.Previous...An area of showers currently across New Hampshire will steadilypush east through this morning, bringing some measurable rainfor portions the area but nothing significant. Amounts acrosscentral and northern areas may amount to a tenth to a quarter ofan inch with up to a few hundredths for areas to the south.Once this batch of showers moves out of the area, mostly dryconditions will prevail into this afternoon with partly sunnyskies and warm temperatures before an approaching cold frontbrings increasing chances for showers and storms into thisevening.CAMs are in pretty good agreement focusing initiation acrossnorthern areas sometime mid-late afternoon with activityspreading southward into this evening. The warm temperatures andcooler temps aloft will provide enough instability to supportthunderstorms, especially across northern and central NH overinto the western Maine mountains and foothills, and a few ofthese could be strong with gusty winds and small hail. Inaddition to this threat, the mean flow is roughly parallel tothe orientation of the convection in what some of the CAMs aredepicting, particularly the HRRR and NAMnest. Although thelocation is uncertain, there is a signal that this could resultin heavy rainfall persisting over some areas which may causesome hydro issues.Farther south, CAMs are not showing much in the way ofdevelopment, but with these very warm temps, development ofisolated-scattered showers along with a couple of storms doesn`tseem out of the question.Central NH and southwest ME are expected to get well into the70s for highs with southern NH closer to 80 degrees as a warmfront slowly advances eastward. Farther east it will be coolerwhere winds will also be onshore, keeping temperatures in the60s.Convection is expected to linger into this evening, especially forcentral and northern areas, but potential for thunderstorms willsteadily wane as instability is lost. Short-range guidance indicatesmost showers will then dissipate by midnight to 2am, but with thefrontal boundary lingering nearby, can`t rule out a few additionalshowers overnight. The main concern then becomes the potential forfog to develop, especially over areas that receive rain, and Iwouldn`t be surprised for some of it to be locally dense with lightwinds and dewpoints in the 50s.
-- End Changed Discussion --&&.SHORT TERM /WEDNESDAY/...Mostly cloudy skies are expected Wednesday with the frontalboundary stalling across the area. More than sufficientmoisture will still be present, and another wave of low pressureriding along the frontal boundary will bring more showers tothe area with perhaps a storm or two. Precipitable water isprogged to be around 1.25", which is quite high for this time ofyear, so will have to watch for heavy rainfall potential onceagain. CAMs and global models are focusing in oncentral/northern NH along with areas from the foothillsnorthward in western ME, which could be some of the same areasthat receive heavy rainfall this afternoon. Have taken more of aconsensus approach to high temperatures with clouds expected tolimit temps to the 60s, but southern NH may still reach thelower 70s.&&.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...A slow moving cut off low pressure system tracks through theMid Atlantic and offshore from Wednesday through Saturday beforedissipating. Another slow moving low pressure system will takea similar track south of New England this weekend.Details...Overall the forecast over the last couple of days has trendedtoward warmer and a longer duration of unsettled conditions. SoThursday doesn`t look quite as wet as they had, but Friday andSaturday now look to continue the chances for showers.Cut off low pressure systems are notoriously tricky for boththe models and forecasters to discern. With these being themain drivers of our forecast this week, it`s worth noting thatfurther changes are likely as well in the coming days. The coldfront approaching from the north looks to be trending a littleslower, and not making as much southward progress. This allowswarmer temperatures into Thursday as the marine air is delayedby at least a couple of days. At the same time, the cut off lowlooks to be tracking more slowly. This causes the forecast tobe quite similar for Thursday through at least Saturday withtimes of showers.At least scattered showers are expected Thursday throughSaturday. POPs on these days are likely to increase in somespots as we get closer in time and certain areas become morehighlighted as seeing a better chance for rain. Overall, thebest chance for seeing the most frequent showers looks to beacross interior areas and the higher terrain. As fortemperatures, highs looks to generally warm into the 60s and 70seach day, with the warmest readings found across westernlocations, and generally cooler toward the coastline.As we get into next weekend, the next system will be followingclosely behind the first one. This likely increases chances forshowers further during the day on Saturday and Sunday. It alsolooks to bring cooler temperatures, as easterly flow brings incooler and damp maritime air. As mentioned, this forecast hasbeen volatile over the last couple of days as the cut off lowregime continues. This weekend`s forecast is subject to change,but that`s the way it looks to be trending at this point. Overthe last week or so, the trend has generally been toward warmerand less wet conditions as we get closer in time, but it`s tooearly to know at this point if that trend will continue thisweekend.&&.AVIATION /08Z TUESDAY THROUGH SATURDAY/...Short Term...Brief restrictions are possible with showers thismorning with mostly VFR well into this afternoon. A slow-moving coldfront will then provide focus for additional showers this afternoonand evening, and thunderstorms may occur as well. IFR restrictionsand gusty wind could accompany showers and storms with the higherpotential for these impacts toward HIE, LEB, and CON. There islesser confidence elsewhere. Showers and storms will diminish incoverage through this evening with a low chance of additional precipovernight tonight. However, low ceilings and fog are expected,especially in areas that receive rain. Additional showers arepossible on Wednesday as the cold front will be stalled across theregion with highest shower coverage generally north of a LEB-LEW-AUG line.Long Term...Generally VFR conditions are expected more oftenthan not from Thursday through Saturday, but periods of MVFRconditions with showers are likely during this time period. Bynext weekend, longer periods of MVFR to possibly IFR look likelywith more showers and some marine fog possible.&&.MARINE...Short Term...Southerly winds continue to increase today as a coldfront slowly approaches. Gusts are expected to remain shy of SCAcriteria, although a brief period of 20-25 kt is possible over theouter waters late this afternoon or early evening. The front thenstalls to the northwest of the water through Wednesday with a southto southwest flow continuing but still remaining below SCAlevels.Long Term...A slow moving low pressure system tracks south ofthe waters from Wednesday night through Saturday. Seas begin tobuild by Friday, with SCA conditions possible by late in theweek and this weekend.&&.GYX WATCHES/WARNINGS/ADVISORIES...ME...None.NH...None.MARINE...None.&&$$NEAR TERM...CombsSHORT TERM...CombsLONG TERM...Clair