textproduct: Boston / Norton

WHAT HAS CHANGED

We increased northwest winds gusts later today into this evening and also issued small craft headlines for all our waters. Otherwise...no significant changes made to the forecast.

KEY MESSAGES

- Scattered rain & snow showers today with perhaps some graupel too. Some locations in the high terrain may see the ground whitened with perhaps up to an inch in parts of the Berks this morning. Becoming windy later today into this evening.

- Dry & cold tonight with windy conditions this evening. Chilly on Wed especially near the coast. Lows tonight in the upper teens and 20s. Highs Wed in the 40s/near 50...but upper 30s/lower 40s along parts of the immediate eastern MA coast.

- Mainly dry & milder weather Thu into the weekend with highs generally in the 50s Thu & 60s Fri/Sat/Sun at least away from coastal sea breezes. Highs may reach the 70s on Mon ahead of a cold front. Dry weather dominates outside a few brief showers possible late Fri/early Sat and maybe sometime Mon.

DISCUSSION

KEY MESSAGE 1...Scattered rain & snow showers today with perhaps some graupel too. Some locations in the high terrain may see the ground whitened with perhaps up to an inch in parts of the Berks this morning. Becoming windy later today into this evening.

A strong shortwave/cold pool aloft will cross the region today. In fact...500T below -30C will create modest instability. Model cross sections indicating enough moisture in the lowest 2 KM of the atmosphere combined with 1000 to 700 mb lapse rates reaching between 8C to 9C! This may be enough to result in a few hundred J/KG of Cape. While today will not be a washout...scattered rain and snow showers will impact the region at times.

Putting all of that together...expect a round of scattered rain and snow showers to cross the region through mid-late morning. This as a shortwave and associated mid level warm front crosses the region. Ptype may be a mixture of rain/snow showers in the lower elevations with no accumulations. Ptype will mainly in the form of snow showers in the high terrain. In fact...a few heavier snow showers may whiten the ground in some portions of the higher terrain with perhaps up to an inch or so of snow in parts of the Berks. Any brief minor travel impacts early this morning should be confined to the highest terrain of the Berks and northern Worcester Hills. And even if there are some brief impacts in the highest terrain...they will be short-lived as temps rise by late in the morning.

Otherwise...the first main shield of precipitation should depart by mid-late morning. However...an approaching cold front coupled with 500T below -30C will result in a self destructive atmosphere. So despite some peeks of sunshine emerging...scattered rain and snow showers will re-develop late this morning and afternoon ahead of an approaching cold front. In fact...given a few hundred J/KG of Cape and temps aloft may see some graupel and perhaps even a rumble of thunder.

Winds will shift to the northwest behind the cold front later today into this evening. It will also become windy with northwest wind gusts of 25 to 35 mph developing with a few gusts up to 40 mph.

KEY MESSAGE 2...Dry & cold tonight with windy conditions this evening. Chilly on Wed especially near the coast. Lows tonight in the upper teens and 20s. Highs Wed in the 40s/near 50...but upper 30s/lower 40s along parts of the immediate eastern MA coast.

Northwest wind gusts of 25 to 35 mph this evening with a few gusts up to 40 mph will usher in dry but unseasonably cold temperatures tonight. These winds should begin to slacken overnight as a strong high pressure approaching 1040 mb builds in from the west. Low temps will drop into the 20s tonight...but some of the normally coldest spots in western MA may see lows drop into the upper teens.

Large high pressure nearing 1040 mb centers itself over our region on Wed. This will result in plenty of sunshine...but rather limited mixing will result in a cool/chilly day especially near the coast. Highs will reach the 40s to near 50 inland...but sea breezes will develop near the immediate coast holding high temps in the upper 30s and lower 40s!

KEY MESSAGE 3...Mainly dry & milder weather Thu into the weekend with highs generally in the 50s Thu & 60s Fri/Sat/Sun at least away from coastal sea breezes. Highs may reach the 70s on Mon ahead of a cold front. Dry weather dominates outside a few brief showers late Fri/early Sat and maybe sometime Mon.

Upper trough over the Northeast shifts east of the region late this week. Westerly flow with above normal height fields are depicted on all the ensemble guidance. This will result in moderating temps Thu and especially by Fri. Many locations should see highs reach the 50s Thu with 60s common on Fri/Sat/Sun. Now it will be cooler at times along the immediate coast with typical sea breezes/modified marine influences this time of year...but overall expect above normal temps. In fact...guidance is showing decent probabilities that highs may reach into the 70s by Mon out ahead of an approaching cold front.

A weak cold front crosses the region late Fri into early Sat with perhaps a few brief showers. Perhaps a few brief warm advection showers sometime Mon too. Otherwise...dry weather dominates given the lack of much synoptic scale forcing.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

Forecaster Confidence Levels...

Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.

12z TAF Update...Moderate confidence today and high confidence tonight and Wednesday.

Scattered rain and snow showers at times today...but much of the day will be dry at a given location. Conditions will lower to mainly MVFR levels this morning into the afternoon across much of eastern MA & RI with perhaps even brief IFR conditions between 16-19z. Across the interior...VFR ceilings will probably dominate but brief MVFR conditions are possible too especially for a few hours this morning. Runways will remain wet even where there is snow in the air given relatively warm boundary layer temperatures. It is possible that there is some graupel too this afternoon given the cold temps aloft.

Winds will be light from the NW across the interior this morning and from the E at 5-12 knots along the coast. Winds will be turning NW later today from west to east behind a cold front and become quite gusty. NW winds will then gust between 25 and 30 knots gusts with a few brief gusts around 35 knots possible behind the cold late today into this evening...before gradually diminishing after midnight. Any lingering MVFR conditions near the coast will become VFR by early evening.

VFR conditions continue on Wed with light N wind becoming light SE with sea breezes developing on much of the immediate coast.

KBOS Terminal...Moderate confidence in TAF. Looking for a windshift from the E to the NW after 19z/20z. NW wind gusts of 25-30 knots develop with brief gusts up to 35 knots possible.

KBDL Terminal...Moderate confidence in TAF. e gradually diminishing aft Outlook /Wednesday Night through Saturday/...

Wednesday night through Thursday Night: VFR. Breezy.

Friday: VFR.

Friday Night: VFR. Slight chance SHRA.

Saturday: VFR.

MARINE

Forecaster Confidence Levels...

Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.

Today through Wednesday...High confidence.

Winds/seas will remain below small craft advisory thresholds this morning...but a cold front will cross the waters later today. Behind this front...northwest winds will gust between 25 and 30 knots with a few gusts up to 35 knots late this afternoon and especially this evening. Small craft headlines posted for all waters. Conditions may flirt with gales for an hour or two this evening...but felt small craft headlines were more representative. Winds/seas will drop below small craft advisory thresholds Wed morning as large high pressure builds in from the west.

Outlook /Wednesday Night through Saturday/...

Wednesday Night through Thursday Night: Winds less than 25 kt.

Friday: Winds less than 25 kt. Seas locally approaching 5 ft.

Friday Night: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers.

Saturday: Winds less than 25 kt. Seas up to 5 ft.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 4 PM this afternoon to 5 AM EDT Wednesday for ANZ230-236. Small Craft Advisory from 4 PM this afternoon to 8 AM EDT Wednesday for ANZ231>234. Small Craft Advisory from 2 PM this afternoon to 8 AM EDT Wednesday for ANZ235-237-255-256. Small Craft Advisory from 5 PM this afternoon to 8 AM EDT Wednesday for ANZ250-251-254.