Active Week Ahead? Latest on Bertha Too
July 5th, 2008
To touch on some of our own weather first....eventually what happens here may influence what happens with Bertha. So we'll tie things together.
So this weekend has been great, hasn't it? Nice conditions, nice temperatures, nice humidity....the whole package! Here's what's up. A look at a surface map from this evening. You can see the stationary front (the one that pushed through here on Thursday with the showers) parked to our south. In fact, some of these showers and storms are just stagnant. There's a Flood Advisory in Sullivan County. So, it's isolated, but heavy rain.
Over the next day or so, that front is going to basically wash itself out. In other words, it will dissipate. So for tomorrow, assuming that front wiggles north just a little bit, there will be a chance of showers maybe just a bit closer to our area. Again, this will be very isolated and for the most part, Sunday's looking like a nice day.
Then on Monday, I'm seeing a small piece of upper level energy leftover on the models in Pennsylvania lifting north and east. I think this may be enough to get some showers and storms going later Sunday night and Monday. So at this point, I don't think Monday is going to be the best day...but if this isn't enough to generate much in the way of storms, then we'll be fine.
At this point, things change. Check out our Microcast's forecasted Comfort Index for Monday evening. This is implying dewpoints well into the 60s. It will become extremely humid Monday night. And on top of that, as upper level temperatures jump 1-3 degrees C, we stand a chance at making a run for 90 degrees Tuesday. I'm keeping us under 90 at this point because I think there might be too much humidity around (dry air heats up much faster than humid air).
So Tuesday, for the most part, looks like a classic summer day: Hazy, hot, humid with a chance of shower and storms. Here's a look at the GFS upper level map for Tuesday evening. I drew in blew the two potential focuses for storms. The lead one I question. But the one over Minnesota will have big implications. The GFS is indicating a pretty long-track MCS (complex of heavy t'storms) tracking from the Rockies to the Canadian Maritimes. Models do a terrible job predicting these things especially this far out, and the track isn't making sense to me. So while this is certainly possible, it isn't likely to me. And I would say that aside from general pulse type storms (with a definitely possibility that we're dealing with an occasional strong to severe storm), I don't see it right now. Does it bear watching? Yes...dewpoints will be high, there will be oodles of moisture and energy for anything to tap into. So there basically is a threat for storms anywhere from Tuesday afternoon through Wednesday morning.
Then on Wednesday, remember that system in Minnesota? Well here it is on Wednesday evening. This is a very potent looking system. Depending on the timing of this, we could be looking at a day of widespread storms and some severe weather Wednesday. But this will usher in a much cooler, more refreshing air mass for later Thursday and Friday. There are serious questions on the timing of the Wednesday storm. Some of the GFS ensemble members are hinting that this will not cross until Thursday. We could even see a secondary system toward Saturday bring a weaker chance of showers and storms. For now, I will be ignoring that latter solution and play the forecast more positive because of better GFS ensemble agreement for later Friday and Saturday.
Here's a look at the Euro (left) and GFS (right) ensemble mean 500 mb anomalies for days 8-10. What does that mean? Basically, what the upper level average pattern will be in the 8-10 day range. Notice a huge ridge building over the Lakes and into the Northeast on the Euro. Sunday through Tuesday has to potential to be one of the hottest periods of the summer. If you'll remember last week I did call for a 90 degree day the week of the 14th. That's just to give you an idea that this isn't exactly a surprise. We've seen this coming for awhile...it's now coming into the shorter range and we can put some sort of timeframe on it. It could be a steamy Boilermaker. Stay tuned on this.
Into Bertha
Here's a look at the current satellite image of Bertha, with the model tracks overlaid. The latest trend in the models is to turn Bertha north a little faster now. What I truly believe happens is this.... Bertha continues on the WNW track, with maybe some favoratism toward the west...for the next day or two. The storm will strengthen slowly into a strong tropical storm by Tuesday or Wednesday.
Here's a look at the GFS on Thursday morning. The "X" in the middle of the map is Bertha, stuck under the subtropical ridge. I think Bertha continues WNW...then eventually ends up just north of the Islands and sits for a day or two (Wed/Thurs-ish). Eventually, the storm will continue on a NW track as the subtropical ridge loses its influence on the storm with the approach of the trough that will bring us our thunderstorms on Wednesday. Bertha would resume a WNW track...if not a due NW track on Friday or Saturday. Then things get interesting. We get a massive ridge building over the Midwest, Lakes and eventually Northeast...what will be bringing us our heat Sunday, Monday and/or Tuesday. I believe this will act as a block to essentially "save" the East Coast from taking Bertha head on. Bertha would slowly lift northward in a weakness between the US ridge and the Atlantic ridge. Eventually a trough which would likely temporarily end our heat (say midweek next week... the 16th or so) would pick Bertha up and kick it out to sea.
If I had to draw a forecast track, it would look something like this. The question becomes...does Bertha get far enough west to clip the NC coast on the way out the door? Or does Bertha line itself up just right to hit Bermuda on the way out? All questions we can't answer right now. And this track could change tomorrow for all we know, but those are my thoughts at the moment.
Posted 4 hours ago
by Matt Lanza.
2 comments
