Saturday, August 8, 2009

All kinds of forecast problems to deal with

Forecast discussion will focus around severe thunderstorm chances tonight or the lack of severe thunderstorms...Yesterday's and last night forecast was right on target...No severe thunderstorms took place across my FA....Lots of heavy rain in my Southern areas...While points in my Central and Northern areas only picked up light amounts,while some places got nothing....

Forecast will be a problem today,and tonight...There are so many things that can wrong with regards to severe thunderstorm threat..First off is last night's/early morning MCS which is now over Central and Southwest WI...Also another areas of showers and thunderstorms over in MN...Still another area of showers and thunderstorms showing up across Northwestern,and parts of Western MN...All of these said areas are pushing to the East...Meantime we find a clearing line in Southwest into South Central MN at this HR..Looking at the SFC Analysis charts this is just about where the warm front is sitting...Here is where the problem come up,and come up rather fast.....Will the warm front push into the FA and how far North will it get..Some models keep the front just into my Southern zones...While some models bring it the warm front into my Northern areas by late tonight....Very strong Cap South of the warm front with 700 MB temps around 12C to 14C...SO if said warm front does blast through the FA today..We will locked under a very strong CAP...That would put the stop to any severe thunderstorms for this afternoon into the evening hrs...Another problem could be the cloud cover....Will it clear out in time for primetime SFC to take place.....Today may be one of those days the cloud cover may help with the severe thunderstorms chances...My thinking is showers and thunderstorms should be pushing out of MN into my Central and Northern areas..Clouds should break up by afternoon this will allow for a strong Cap to form holding severe thunderstorms at bay...Thinking for tonight is as the 700 MB level cools the Cap will be breakable...Another round of MCS should be in the cards......Now looking at radar I see more thunderstorms a forming in Western MN rather fast...So thinking above may not play out as forecasted.....I'm going to bank on some clearing around the noon hr....Destabilization will occur rather fast along and North of the warm front...That would be the main areas to see severe thunderstorms...South of the warm front Cap will hold it's own.....Now if severe thunderstorms do get going later this afternoon into this evening,main threat would be damaging winds and large hail..Threat for tornadoes will be confined to MN along the triple point as storms first get going.....Once again some many things can go wrong with this forecast...Nothing is set in stone for today into this evening....Tonight models do agree that another thunderstorm complex will form...The threat from the MCS would be heavy rain once again....So here we go again where will this complex set up....To many questions still...So where ever the MCS setup heavy rainfall will be likely which would bring the chances of flash flooding in the cities and low land area....Temps going to be very tricky today...Just like yesterday we never got out of the 60s for highs...Have to look to see if we broke any cold high temps yesterday.....Anyway where the clouds hang on look for temps to be in the middle to upper 70s maybe an 80 or two..In my Southern areas temps should reach the lower to middle 80s..Sunday does look to be the warmer day...Highs in the middle to upper 80s...I think the 90s will stay South of my FA....As clouds will keep temps in check,along with the higher dewpoints...Temps do cool off into the lower 80s for Monday and Tuesday...This will be short lived as models want to bring in WAA with the return flow...That means the heat and higher dewpoint shall return by midweek......