What will happen here with remnants of Isaac?

August 29th, 2012 at 4:35 am by under Weather

Isaac Will Push Heat Toward Area

The first effect of Isaac for the area may be a little unexpected as hot air which will blow off from the top of storms associated with Isaac begins to filter into our area Thursday afternoon. This will take a quiet and cool pattern and change it into some late August heat and humidity. This warm air will continue to surge into the area through Friday making it very uncomfortable with highs in the 90s and tropical humidity levels.

What Will Happen With Remnants?

The biggest question that still remains for our area is what will happen with the remnants of Issac. Most of our mathematical models have continued to bring the bulk of the moisture into northern Indiana through Sunday. This is still a distinct possibility this weekend, but the latest data indicates that the heaviest rainfall may be just south of our area late Saturday and early Sunday. A second model brings the moisture well south of our area. There is still quite a bit of uncertainty with this track as this system continues to make landfall we will have a little better idea of it’s track over the next 24 to 36 hours. Areas that do see the heavy rainfall could see up to 3″ from this “extra tropical’ system. Of course these rainfall amounts will be minimal compared to areas in the south and southeast which will experience anywhere from 6 to 16 inches of rainfall.

3 Responses to “What will happen here with remnants of Isaac?”

  1. Kimoeagle says:

    It would appear that GFS is forecasting Isaac to come out of the west and put Fort Wayne in its path.
    Here’s what IWX is currently saying:
    THE OBVIOUS FORECAST CONCERN IN LONG TERM IS REMNANTS OF HURRICANE
    ISAAC AND IMPACTS ON OUR AREA WITH HEAVY RAINFALL POTENTIAL THIS
    WEEKEND. 00Z MODEL SUITE HAS DONE NOTHING FOR CONFIDENCE FACTOR AND
    ACTUALLY INCREASED THE UNCERTAINTY EVEN MORE. 00Z OPERATIONAL GLOBAL
    MODELS HAVE TAKEN EVEN MORE OF A SOUTHERN SHIFT WITH EVENTUAL TRACK
    OF REMNANT LOW. AFTER A NORTHWEST THEN NORTH MOVEMENT THROUGH
    MO…GFS…ECMWF AND GEM-NH TAKE LOW ALMOST DUE EAST THROUGH CENTRAL
    OR SOUTHERN INDIANA THIS WEEKEND. 00Z GFS ENSEMBLE MEMBERS SHOW
    CONSIDERABLY LARGER SPREAD WITH LOW TRACK BUT A DEFINITE SHIFT
    SOUTHWARD. THIS WOULD KEEP AXIS OF HEAVIEST RAINFALL SOUTH OF OUR CWA
    WITH ONLY SOUTHERN THIRD OF CWA LIKELY SEEING ANY SUBSTANTIAL
    RAINFALL AND FAR NORTH REMAINING DRY. ON THE FLIP SIDE…00Z
    HURRICANE MODELS WERE STILL CLINGING TO A FURTHER NORTH SOLUTION
    WITH REMNANT LOW TRACKING THROUGH NORTHERN INDIANA. A QUICK LOOK AT
    SOME 06Z DATA SUGGEST THESE MODELS ARE NOW SHIFTING SOUTH TOWARD THE
    GLOBAL MODELS WITH A TRACK THROUGH CENTRAL INDIANA. THE CULPRIT IN
    UNCERTAINTY REMAINS STRONG RIDGE THAT WILL BE ACROSS THE MIDWEST
    FRIDAY. WEAK FLOW ALOFT WILL ALLOW SYSTEM TO SLOW AND BEGIN THE SLOW
    DRIFT EAST. STILL A LOT OF UNCERTAINTY DEPENDING ON STRENGTH OF
    RIDGE BUT WILL SIDE WITH A MORE SOUTHERN TRACK. THIS WILL KEEP
    LIKELY POPS ACROSS FAR SOUTH AND CHANCE POPS NORTH.
    I have no doubt that we will see rain here in Angola, one way or the other!

    1. Greg Shoup says:

      While I agree with this thinking, in looking that the two model runs the GFS has been consistently, with one small blip yesterday, taking the remnants across northern Indiana. There is still quite a bit of uncertainty here I agree. We do respect and take into account was the NWS discussion is forecasting. However, we have four meteorologists and most of the time we try to be a step ahead in our forecasting. Here’s the reason, the current forecast from NWS is from yesterday at 3:30 pm with very little strange. That’s because of the governmental structure of the orginization. They do not like to change the forecast drastically from shift to shift until the 3:30 forecast. Our thinking right now is that the Global forecast solution has been the most consistent and is taking the extra tropical moisture across northern Indiana. What is lacking here is consensus in models which we always like to have. However, I’m certainly not ruling out heavy rainfall across northern Indiana for this weekend and unless something changes drastically in the next couple of runs I don’t believe we will see drastic changes in our forecast here. But as they menitoned in the discussion there is some uncertainity until we can get some indication of the actual movement of the extra tropical moisture. I will tell you that the precipitable water table for this area, (which is the amount of water the column of air holds) for this storm is about 2.50″ that’s about 125 percent of normal August precipitable water amounts. The Quanitative Precipitation at this time is putting up to 7 inches of rainfall over the Lafayette are for Saturday and early Sunday. This certainly is an early forecast and that heavy rainfall may get shifted north to Milwaukee or south to Kentucky depending on which solution you are using. Just my thoughts right now. One more point and I will quit rambling here, If you look at the NHC track which I have in my blog entry for today you will see that yellow area. While the NHC has the low just about 50 miles south of Fort Wayne the yellow area is the ‘cone’ which is about a 500 mile radius. This is because of the uncertainity and shows that we could see the heaviest rainfall in northern Indiana or north to Milwaukee or south to southern Indiana and northern Kentucky. Those are my thoughts right now.

  2. Kimoeagle says:

    Just looked at the NWS/IWX ‘long-range’ at 2:54pm, and they are in agreement regarding the “uncertainty”.It appears that the trailing “ridge” from the High coming through may influence its ultimated direction. Just a guess.
    Thanks for your input, Greg!