Tag Archives: Tropics

Showers Bring Heavy Rain Tonight Before Cooler And Drier Conditions Early Week

Hello everyone!

A cold front is incoming this evening and will cross the area tonight and early tomorrow morning. Showers will accompany this front with heavy rain and possibly a rumble or two in the far south. No severe weather is expected, just heavy rain. Rain will be heaviest in the north where up to an inch is expected. It will be lightest in the south where some areas may only pick up a quarter inch. Rain races NE Monday morning with clearing skies and gusty NW winds Monday during the day. Those NW winds will bring much cooler and much drier air in for Tuesday and Wednesday. An approaching front will bring SW winds and warmer air for late week with showers possible by the upcoming weekend. Just as a reminder, current information on tropical weather is now on the new tropical weather page.

4:00 PM Observations Verifying Today's Forecast
4:00 PM Observations Verifying Today’s Forecast

Today’s forecast worked out pretty well and the only glaring error was that there was more sunshine than expected. So far I haven’t received any complaints about that! Clouds are still slowly filtering in from the west while the Midcoast got their predicted marine fog. Temps look good with the only glaring error being lower temps (60’s) along the midcoast where the fog hasn’t let up. I have doubts about the 88 degree reading in Concord as no other station in that area is above the low 80’s but if that is actually accurate, that would be the other mistake as far as temps go. Overall, I’m pretty pleased with today’s forecast.

8 AM Upper Air Observations Showing The Overall Pattern. Image Credit: Meteocentre
8 AM Upper Air Observations Showing The Overall Pattern. Image Credit: Meteocentre

A deep trough is located over the Great Lakes this evening with an associated surface low near the SE corner of Hudson Bay. Ahead of the trough, strong blocking ridging exists over the Canadian Maritimes. In between, SW flow is bringing warm moist air northward. Strong NW flow behind the trough and attendant front will bring cool, dry air sourced from Northern Canada before SW winds ahead of the digging trough in the Pacific NW bring warmer air for the upcoming weekend.

HRRR With An Idea Of What The Radar Might Look Like Early Tomorrow Morning. Image Credit: Weatherbell
HRRR With An Idea Of What The Radar Might Look Like Early Tomorrow Morning. Image Credit: Weatherbell

In terms of what to expect tonight, showers are just now moving into far Western VT which means that western NH will start to see drops in 2-3 hours. It won’t be until well after dark that western Maine starts to see the rain move in. The rain will be associated with a single N/S band containing heavy rain and possibly a rumble or two in the far south. The band will be wider and heavier in northern areas resulting in higher totals there. The HRRR map above illustrates the setup well. The map is valid at 4:00 tomorrow morning. Rain will move out of Portland by 6 AM and out of the midcoast by 8. Clearing will follow.

12Z GFS Showing Gusty NW Winds Tomorrow. Image Credit: Weatherbell
12Z GFS Showing Gusty NW Winds Tomorrow. Image Credit: Weatherbell

Behind the front, gusty NW winds are forecast to develop. Winds could gust over 30mph at times as cooler and drier air works into the region. Look for these winds to quickly downslope the coast to sunny skies while upsloping may postpone sunshine for the mountains. Eventually, the air will become so dry that even with upsloping, the mountains will become sunny by afternoon. Dew points are forecast to drop to near 40 by tomorrow night. As winds settle down tomorrow night, temps will fall too. By Tuesday morning, the first fall like chills will be felt with temps bottoming out right around 40 in the north and 50 in the south with very dry air.

12Z GFS Showing Warm SW Winds Ahead Of An Approaching Front Late Next Week. Image Credit: Weatherbell
12Z GFS Showing Warm SW Winds Ahead Of An Approaching Front Late This Week. Image Credit: Weatherbell

Not ready for fall? Not to worry. By late in the week a front will be approaching from the NW and ahead of it SW winds will bring in slowly increasing warmth as well as humidity. While conditions won’t be stifling, the word sticky will once again come to mind by the upcoming weekend. As far as precip goes, the front won’t have a lot of dynamics associated with it and so scattered showers/storms are likely the most we’ll get from that front. After that, dry and warm conditions are likely to kick off next week.

Be sure to check out the new tropical weather page to keep tabs on the Atlantic disturbances 90L and 99L without the hype you may see on social media. The official NHC forecast, my forecast, and links to all the tropical weather information you need to take your own look at the tropics is all there. Check it out!

-Jack

Tropics heating up…

After an inactive start to the season, we are about to turn over a new page in the tropics. The main driver will be the Madden-Julian Oscillation, a pattern of shifting winds that increases thunderstorm growth that returns to the same area every 30-60 days. This pattern will make itself known later this week into this weekend and will continue through mid September. For those of you who follow tropical weather, we saw this pattern in the Central Pacific and the Eastern Pacific these past few weeks which was why there was so much activity there. (2 storms in a week in the Central Pacific is VERY active) We already have a few interesting African Waves to look at…

IR1

Our 2 African waves that need to be watched. More are expected to arrive from Eastern Africa over the course of the next few weeks.

Another unusual thing about this particular MJO pulse if there have only been 2 of this extreme caliber in recent memory. In those 2 cases, 68% or 21 out of 31 depressions formed into hurricanes. The models are already excited showing nearly every wave evolving into a system. Most of which will recurve due to a high pressure system that usually steers it into the Caribbean being too weak to have the westward effect on storms.

ta111

The position of the Bermuda high is further westward and weaker allowing strong storms to recurve easily out to sea.

However, if a storm is weak enough it will continue westward into the Caribbean where so called “rocket fuel” is located allowing for rapid intensification under the right circumstances.

ta1111

This map depicts a possible track for a weak storm that can continue westward despite the position of the high.

TCHP1

This map shows where the most possible energy is for a tropical system to feed on.

I believe the last time a storm traversed this area was in 2008, 5 years ago when Gustav moved from the Western Caribbean into Cuba. This is also the same area where Wilma intensified into a monster 882 mb, 180 mph, cat 5 hurricane. The other danger that lies here is that any storm that forms and intensifies WILL affect land and has a 95% chance of making landfall somewhere. The good news is that no model currently forecasts a storm to develop here however its an important area to watch nonetheless.

A further update on the tropics can be expected in a few days or when a system develops or is a threat to develop.

-Jack