This Week’s Forecast For Week Of March 8, 2015

20150227_DallasSnow01
Source: Wikimedia

Even with March in, it has been rather cold. North Texas has gotten a lot of snow. It is like that Old Man Winter does not want to leave despite the calendar saying so. Not surprisingly, the coldest air is over North Texas. East of the Rocky Mountains has been cold last week. Alaska and Arctic Ocean have been quite warm.

20150309_SurfaceTemperatureAnomaly_NH

Now, why it is cold in some areas, while warm in others. Look no further than the upper part of the atmosphere.

20150309_500mb_GeopotentialHeightAnomaly_NH

What do I see here? I see upper level ridging over Alaska, which is negative East Pacific Oscillation (EPO). There is upper level troughing over Northeast Canada and Greenland, which is positive North Atlantic Oscillation (NAO). Cold blasts can happen with a negative EPO and positive NAO. There is also upper level ridging over Northern Russia. Ridging over Arctic areas causes cold air to be shunted down south. Troughing keeps the cold air over the Arctic.

This week has started rainy in Texas. Beneficial rain that puts a dent on the drought plaguing Texas. Here is a 132 hour rainfall total forecast til Sunday.

20150309_AccumulatedPrecipitationTotal_USA_132Hour_1800Z

The GFS and Canadian forecast 0.50 to 1.50 inches of rain. The Canadian goes as high as 3 inches of rain between now and Sunday. Rain will be the main headline for the Southeast as the same system over Texas traverses eastward carrying Pacific and Gulf of Mexico moisture. This is more of an El Nino pattern, which we are in. The GFS forecasts less rain for Alabama and Florida Panhandle. On the other hand, Canadian has up 5 inches of rain for Alabama and Florida Panhandle. The GFS has the heaviest rain over Tennessee.

What can the past hold for this week? Here is a 6 to 10 day analog forecast.

20150309_6To10Day_AnalogForecast

3/13/1972-A slow moving cold front triggers heavy rain over Southeast Texas on 3/20. Bush Intercontinental: 7.47″; Hobby: 0.64″; Independent Heights 7.65″; Halls Bayou 9.50″; Galveston: 0.82″; College Station: 0.07″. Record calendar day rainfall total for Bush.
3/1/1994-A cold front comes on 3/9 and thunderstorms form ahead. Bush Intercontinental: 1.18″; Hobby: 1.20″; Galveston: 1.26″; Second wettest 3/9 for Bush and Galveston. The cold front brings a light freeze.
3/24/1993-Southeast Texas saw rain from 3/19 to 3/23. Heavy rain falls on 4/3-4. Bush Intercontinental: 3.68″; Hobby: 2.17″; Galveston: 0.81″. 3.09″ falls at Houston on 3/9, setting highest one day rainfall total for that date.
3/2/1993-Start of the “Storm Of The Century”, also known as ’93 Superstorm. A strong extratropical low pressure system forms in the Gulf of Mexico ahead of a cold front. The storm rapidly intensifies and becomes a large and powerful storm. Derechos and storm surge are experienced in Florida, while Appalachia and Northeast are pelted by heavy snow and blizzard.
3/15/1995-A March heat wave strikes east of the Rocky Mountains and Northern Canada betweem 3/18 to 3/23. Many areas see near or record highs during that time.
3/5/1992-Heavy rain and flooding hits the Houston area on 3/4. Many areas see 4 to 10 inches of rain during the event.

Some of the analog dates really stand out, especially when it comes to heavy rain. One had a unusual March heat wave. If we use 6 to 10 day analog forecast, this suggests it could be a rainy one. Anyways, let’s look at the 8 to 14 day analog forecast. By the way, it is wrongly labeled as 6 to 10 day forecast as it centers around day 8. Do not worry, this is a 8 to 14 day analog forecast.

20150309_8To14Day_AnalogForecast

4/5/2004-Heavy rain falls on 4/10-11 in Southeast Texas. Bush Intercontinental: 3.27″; Hobby: 1.31″; College Station: 0.89″. 2.57″ falls on 4/10, highest rainfall total for that date.
4/4/2007-A cold blast hits Texas on Easter Weekend. Snow and sleeted is reported north of Houston. Many areas see near record lows during the cold blast including Houston, which saw 38°F on 4/7 and 37°F on 4/8.
3/5/1984-March 1984 starts cold with a low of 31°F at Bush Intercontinental on 3/1.
3/29/1993-Southeast Texas saw rain from 3/19 to 3/23. Heavy rain falls on 4/3-4. Bush Intercontinental: 3.68″; Hobby: 2.17″; Galveston: 0.81″. 3.09″ falls at Houston on 3/9, setting highest one day rainfall total for that date.

In the long term analog, heavy rain or cold blasts are the issue. There was a cold Easter in 2007. If I use the 6 to 10 day and 8 to 14 day analog forecast, it looks to be cooler and wetter than normal for the start of March.

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