Prologue to Winter Weather Forecast 2013/2014 REVISED

The last two winter seasons have been less than satisfactory for snow lovers here in Louisville and most of central Kentucky. Downright abysmal actually. However, change could be coming for the upcoming winter.

Persistent atmospheric patterns kept moisture to a minimum for the area during the 2012/2013 winter. Prior to last year, persistent atmospheric patterns kept temperatures warmer than average during that winter.

Will this winter be dominated by persistent atmospheric patterns? Most likely not. Let me explain.

I believe drought played a major role in the nation's weather patterns during the past two winters. Some areas of the country received substantial snow totals while others received little accumulations.

Severe droughts are a result of climatic patterns that often can influence or dictate weather patterns. They create subtle boundaries that may affect upper level winds. For example, storm systems driven by the upper level winds either go around these semi-permanent anticyclonic features that are a result of drought or its associated moisture may be sapped by the surrounding relatively drier air.

This year's drought situation has improved significantly over the South and Midwest sections of the U.S., an area where our weather systems tend to develop and attract our attention. Perhaps, this is an indication that the climate pattern has begun a transformation. That should increase variability in weather patterns across the country, especially for our region. Does that mean we here in Louisville will get more snow?

Increased variability will lead to weather systems behaving more normally this winter. In other words, expect a nice blend of cold spells and periodic warm events that could spawn severe weather. Look for a few systems to come out of the Rockies and find their way into the Ohio Valley.

As is usually the case in these parts, a battle ground for precipitation type will affect who gets what and how much. I believe it will be a more exciting winter than the previous ones. That's all I can really say about that.

MS

Bracing for More Water Issues

Over 5.50" has fallen at my house since 11:00am yesterday. A large shield of moderate to occasionally heavy rain is moving in from the west, promising to dump another 1-2" before tapering later today.

The ground near my house has handled the water mightily, relatively speaking. News reports coming in from the Metro area are impressive, if not scary. Lots of water rescues.

I'm expecting to battle water issues in my basement for the rest of the day....

MS

Stormy Night

As of 10:00pm, I've recorded 3.75" at my house here in Valley Station (southwest of KSDF). Looking at Radar returns, it looks like this is just the beginning of multiple episodes of heavy rainfall lined up for tonight.

Flash flood warning has just been posted for the Louisville area.

Water is starting to seep into my basement. Once I get 4", water generally tries to get in (I'm going to have to get that fixed)

I wish the atmosphere would hurry up and get overworked so rainfall will diminish. But, it looks like rotating storms out west of Louisville may move in by midnight. If anything, looks like more heavy rain on the order of 1-2 additional inches overnight.

And they're still calling for rain tomorrow???

MS

Rain Not Looking Impressive Today for Louisville

A welcome cold front (actually 2 fronts) resides in central and northern Indiana. Along the first front, a broad band of weakening showers is sagging south while main energy shunts east.

Infrared satellite showed warming cloud tops as the line approaches our area. Convective temperatures are near 85-86 degrees (and that may be conservative). Yet, our temperatures may struggle to reach that. Therefore, I don't see any thunderstorms for the area with this initial band of weakening showers.

Thunderstorm chances with this initial band look better south of Louisville and to the east where main energy and better instability reside.

However, am noticing colder cloud tops trying to form south of Chicago who has cleared out nicely. Their dewpoints are running in the upper 50's as of this writing. There is a chance we could see a thin line of showers and thunderstorms later this afternoon as this secondary front surges southward.

Precip amounts for Louisville should be in a range of 0.1 to 0.4 inches today. Some areas near our area could get between 0.5 to 0.75" but should be confined again to our south and east where convection is highest.

Nevertheless, looking forward to those cooler temperatures!

MS

What Are Louisville's Rain Chances?

So far, it's been a guessing game as to when Louisville will see measurable rain. Today, I'm seeing that window shrink. Radar looks like a ring of water around Louisville.

Infrared satellite has been showing warming clouds west of the area and a gradual weakening of its associated complex. However, am starting to see additional convection firing out toward Paducah. These are beginning to form an outflow line of storms that should take over the rest of the afternoon as it moves east.

The bulk of the storms may stay just south of Louisville. But, our chances of getting wet are increasing. One of the short-term models is showing precipitation breaking out near our area after midnight.

Rain may be heavy as evidenced by parts of the Bluegrass region who got swamped last evening.

MS

Wet Week Ahead? (Aug 5-12)

A change in the weather pattern is in store for the region this week. A persistent northwest flow has dominated most of our summer, but the atmospheric pattern will change to a more zonal flow (w to e) this week.

A large fetch of moisture is forecast to impact the region by the middle of the week. Depending on the front's position, periods of heavy rain could set up for some. Widespread 2-3" amounts are expected this week.

A caveat is in the front's position. While the WPC paints widespread amounts, it must be understood that the potential exists for these amounts if any disturbances interact with the slow-moving or stalled front and its favored location.

Heaviest rains at this time appear to reside south of the Louisville area. However, until a better understanding about where the front will be located the next few days, it's more of a guess than a forecast.

If heavy rains do materialize, some areas in our region will have to worry about flooding concerns.

MS

MikeS 66 Index JULY 2013

The official statistics are not out yet for the month of July. However, my index of 66 random locations comprising the various climate regions of the contiguous United States revealed some interesting data.

It was a month dominated by persistent weather patterns. A large ridge in the west. A cutoff low in the Gulf of Mexico. A large upper level low spinning across the Hudson Bay. A bulging southeast ridge. Sometimes, it was a matter of the have's and have not's, especially when it came to precipitation.

Overall, the temperatures averaged out right at normal. However, the overall precipitation came in well above normal. Four of the six climate regions produced above normal readings with the southeastern U.S. coming in with some of the wettest July's in years. This was due to a persistent onshore flow of moisture resulting from a stationary non-tropical low spinning just south of the Florida panhandle.

Now for the numbers...

High Plains 73.4 average of high and low
                                    0.4 Below Normal (temps)
                                    14% Below Normal Precipitation

Midwest  72.3
                              0.3 Below Normal
                              25.8% Above Normal Precipitation

Northeast  75.8
                                 2.2 Above Normal
                                 25.8% Above Normal Precipitation

Southeast  80.0
                      1.2 Below Normal
                                 64.3% Above Normal Precipitation

Southern   80.9
                      1.2 Below Normal
                                 3% Above Normal Precipitation

West         77.1
                     1.7 Above Normal
                               13.7% Below Normal Precipitation

You can tell how the western ridge affected temperatures and precipitation there. Extreme heat prevailed over much of the desert areas. Also, the persistent upper low in the Gulf produced enormous amounts of rain. What I found staggering about those numbers was that normal rainfall amounts start ramping up during tropical weather season. In fact, places like Tampa FL and Wilmington NC generally see at least 7" on average for the month of July. Although Tampa exceeded their average, Wilmington's 5.64" for the month was a stunning 1.84" below normal! There were no tropical systems in July that directly affected the U.S. but many locations added to their June totals making inroads on one of the wettest summers on record.

As for the Northeast, I was there when temperatures soared well into the 90's and touched 100 in a few areas. The dew point was high adding to the discomfort. Power outages occurred. Children often flocked to fire hydrants to keep cool. Some of the places I visited were running on generators just to cut down on the high energy demands.

Here's the final tally for the United States as a whole:

United States (48 contiguous) 76.6
                                  0.0 Average
                                        14.2% Above Average Precipitation

MS