The Portland plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
MILE1
TODAY
Today in Portland
NWS forecast and National Blend of Models · updated 4:00 PM EDT
RIGHT NOWRobertson Field Airport (K4B8) · 5:35 PM
67°SunnyFeels like 67° · high of 66° near 5 PM
WindCalmno gusts
Humidity75%rising to 100% by morning
Pressure29.98 in →steady
Visibility9 mihazy
CloudsClear
UV index—no forecast
Dew point 58° · Comfortableabout the same for three days
DryComfortableStickyMuggyOppressive
NEXT RAIN
Friday30% chance · showers
LIKELY AMOUNT—amounts come within 3 days
LAST RAINSept. 281.33 in · 1 dry day
ALERTS & OUTLOOKS
No watches or warnings for Lower Connecticut River Valley Planning Region
NWS Upton and the Storm Prediction Center · checked 5:45 PM
SUN & MOON
↑ 6:44 AM6:36 PM ↓
11 h 51 m of daylight, 3 minutes less than yesterday
Waning gibbous, 88% lit. The Harvest Moon was full Saturday.
AIR & POLLEN
18
GOODAir quality index · ozone
Tomorrow: 39, good. No pollen source yet.
The next three days, hour by hour
Sky: clear, cloudy, nightRain likelyNational Blend of Models
Forecast, with the range 8 in 10 ensemble members agree onNormal, about 80° / 62°
TUESept. 29Partly cloudy
66°53°
0% rain—NW 3A
WEDSept. 30Partly cloudy; warmer
74°58°
0% rain—SW 1B
THUOct. 1Partly cloudy
77°64°
0% rain—SW 6C
FRIOct. 2Chance of showers
81°58°
30% rainup to 0.1″NW 8B
SATOct. 3Partly cloudy; cooler
69°48°
10% rain—NNE 2B
SUNOct. 4Chance of showers
64°49°
40% rainup to 0.6″S 2C
MONOct. 5Mostly sunny
64°43°
10% rain—NW 8C
How sure are we?AModels agree: highs within 4°BSome spread: within 8°CWide spread: check backRange from the National Blend of Models percentiles · graded on Forecast Scores
AIR MAIL
Where today’s air came from
The air arriving over Portland about 5,000 feet above the ground was over the Atlantic off the Carolinas three days ago, and over New England a day ago, about 1,250 miles back along its path. Near the ground the air came from Canada; at 10,000 feet, from the Atlantic off the Carolinas. Traced back 72 hours through NOAA’s hourly RAP analyses and the GFS beyond them, nine paths at each of three heights.