The tropical disturbance hanging out over Florida since the 23rd – (Fort Myers, Florida, has received 14.1 inches of rain since last Wednesday) is moving up to the Carolina’s – this storm is expected to stay mainly off the coast then move back out to the Atlantic.
The Atlantic is warm and becoming more active – the next system is moving well off the coast of Africa, I have a lot of maps open this morning and am trying to keep them straight – the coffee is trying to clear out the cobwebs. Below is the current NHC (National Hurricane Center) graphic.
Next are the forecast graphics for 10 (Irma) and Harvey
Here are the HRRR models I ran this morning for the Eastern seaboard and Texas/Louisiana.
HRRR and Futurecast models runs are for 12 hours beginning at 7am – a second model run begins at 3pm
Overall expect cooler than normal temperature and little if any precipitation into the coming weekend. By the middle of next week we will likely see some truly chilly temperature, cooler than we have seen since at least May of this year.
A departing upper level storm system will bring the risk of afternoon showers and possibly a thunderstorm east of Grand Rapid otherwise the fog of early this morning should burn off by 9 am or so. High pressure ridges in for tonight into Wednesday ahead of significant early fall cold front that will come through the area dry early Thursday.
Once again through we could see widely scattered showers and thunderstorms east of Grand Rapids. Wednesday should be the warmest day of the week with highs near 80. It will be much cooler Thursday into Friday behind the next cold front. Below is the GFS temperature forecast through September 14.
Day and Week Planner
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The next two days will likely be the warmest of this week which is not saying much actually. There is a risk for afternoon convection (model sounding show no cap to stop it) both today and tomorrow but if it happens it will be east of Grand Rapids and more likely near and east of Lansing.
Fog will be an issue this morning and tomorrow morning too. Light winds and mostly clear skies will help that cause. The water vapor loops show an upper level system to our south moving northeast. This will bring the greatest risk of convection today east of the GRR CWA. Still the model sounding do show convection as being possible.
Winds will for the most part be light and variable so not much forcing there either. Later in the day winds should become light northwest so that in combination with the upper level system lifting or our east I would think chance pops for our eastern CWA should do fine for today.
While high pressure builds into for Wednesday ahead of that next frontal system there is still enough instability for convection in the afternoon. It should be noted that the SPC convective outlooks have us in general thunder for today and tomorrow.
There is a digging northern stream jet streak that will bring a Canadian Polar Air into Michigan for Thu into Friday. This is one of those back-door cold fronts (drops southward instead of moving east or southeast). These fronts are for the most part dry in Southwest Michigan and this one will be no exception. I do have low chance pops during the early morning hours Thursday just ahead of the front but do not expect much from this.
The jet core that drives this stays north and east of this area so we do not get into the deep cold air which limits instability. So the bottom line to this is not much in the way of rainfall expected through Thursday and temperatures will likely not get above normal either. .
Canadian high pressure will continue to build in Thursday night through Friday and bring fair and seasonably cool wx with high temps in the upper 60`s to lower 70`s and low temps in the 40`s. Temperatures will moderate Saturday as southerly flow develops on the back side of the departing ridge. This in conjunction with some sun will help to boost high temps well into the 70`s.
A weak front moving in from the northwest will bring a small chance of showers Saturday night. A consensus of latest 00z medium range guidance continues to suggest that remnant showers from the former tropical system will stay south to southeast of our fcst area.
Temperatures will remain seasonably warm Sunday into Labor Day as south to southwest flow redevelops out ahead of a strong cold front which will approach on Labor Day. This front will bring potential for showers and perhaps some thunderstorms early next week.
A consensus of latest 00z medium range guidance/guidance trends suggest that an unseasonably cool airmass will move into the Great Lakes region for the mid to latter portion of next week. This will occur as a high amplitude upper level trough digs and amplifies over our region. Temperatures will average at least 10 to 15 degrees below normal for this time of year by then and this notion is also supported by the latest cpc 8-14 day outlook.