Northwest flows are tricky…disturbances generated in the Rockies or the SW rotate around the core of the ridge and periodically move in this direction. For most of the summer (thus far) the core of the heat has been almost on top of us or nearby to keep this type of flow across the northern Plains. Now as the core of the heat has shifter SW of the immediate area, we are in this NW flow region. Here is what I’m talking about…take a look at the 500 mb map, about 18K feet up, showing the general flow.
Click on that image to make it larger…
So the disturbances generate rainfall, Manhattan today picked up .11″ of rainfall. Actually they even generate MCV’s or Mesoscale Convective Complexes. It is really apparent today. Here is the visible satellite picture from early this afternoon. The swirl in the clouds is pretty apparent.
More importantly the disturbance generated clouds and those clouds, while thinning are keeping highs in the 90s for the region. The same scenario may occur again tomorrow. The thing about it is, without the clouds. we’re in the 100s easy. Computer projections have been running 105-110° lately, obviously too high with the cloud cover that is moving through the region.
There should be another disturbance tonight across the Plains states, that will move this way tomorrow AM. The RAP is showing something across NE later this evening.
It too should move east then ESE then SE…IF we can get this thing here earlier in the day then the rain chances would be higher…the later in the day we go, the the higher likelihood of these things weakening and falling apart before we get the needed rainfall.
On the rainfall subject, the news still is not good. While there will be chances for a few days nothing really stands out. There should be a stronger front moving through on Saturday. The timing though doesn’t look the greatest for a lot of storm coverage. Should the front slow down and move through later in the day, that could change, because this front is rather substantial. Highs should drop to more seasonal values on Sunday and Monday with lows down into the 60s(?)
Concerning the drought, I’m still surprised when TV weather people show year to date rainfall numbers as if the issue for the drought has been going on for the whole year. In my opinion this drought has been a 4 month issue now…so while the year-to-date numbers are about 10″ below average, the numbers since April 1st are close to 13″ below average. The 1st 3 months of the year were OK for precip for many areas. There were some dry spots but really this drought has been a 4 month feature that continues to lengthen. Here is a graphic from the NWS showing how the drought has been generated and how it has expanded across the region in the last 2 months or so
It’s a great graphic.
Speaking of which, here is a look at how the drought has been generated through the year…
That’s about it for today…I’ll be working the AM/Noon shows tomorrow while KR takes a couple of days off…see you in the morning.