May 7, 2015 11:43 PM
NH1 Weather Insider with Joe Joyce: May 8, 2015
NH1 Chief Meteorologist - NH1.com
Onshore winds develop Friday behind a back door cold front which will push in from the northeast as high pressure slides down from Nova Scotia. This will bring a dramatic change to the weather for New Hampshire for one day. After being in the 80's Thursday, some of us along the coastline will only be in the 50's on Friday! Farther west in the valleys and away from the ocean is where warmer temperatures in the 70's will be found. Overall, another fine day with sunshine, and some increasing afternoon clouds along with cold front. It will be a fascinating day to watch the temperatures as it will a short distance of a few miles could bring a 20 degree change in temperature.
Onshore winds will not only bring cooler temperatures, but also an increased Relative Humidity...as temperatures will be closer to their dewpoints. This will alleviate the brush fire danger which has been so prevalent this week.
Despite the brief cool down, there is still plenty of warmth in the pattern. The upper level ridge sitting over us will nudge slightly north over the weekend. The backdoor front with onshore winds will lift out with a return to a warmer SSW flow. Highs will be climbing back into the 70's on Saturday nearing 80. with Partly sunny skies.
Sunday will see the warmer air settling in again across New England along with rising dewpoints inot the lwr 60's. Highs should climb to 80-85 degrees for most, 70's at the coast. A more humid feel to the air with likely a few more clouds as well.
We will start to see the threat of showers and thunderstorms shift farther south Sunday thanks to a cold front across the Canadian border. The best chance of any scattered showers or storms will likely be across the north country Sunday afternoon, closer to the stalled front. This front will sag farther south Monday for an increased risk of scattered showers and thunderstorms along with the threat for some heavy rain. We could definitely use the rain! A wave of low pressure will ride along this stalled front and keep the risk of showers going into Tuesday. Once this sweeps through a brief return to cooler more seasonal air in the 60's for the midweek.
Subtropical storm ANA off the South Carolina Coastline with winds up to 45 mph in the center of the storm. It is not a totally warm core system, thus the term "subtropical". It is expected to get a bit stronger and transition into a full tropical storm soon where it will lash the coastline of the Carolinas for the next few days with gusty winds and rain. Some of this moisture could get entrained into the front that will eventually sweep through Tuesday.