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Spring Outlook For Arkansas (March Through May, 2013)
 
Precipitation forecast for December, 2012 through February, 2013 (courtesy of the Climate Prediction Center).
In the picture: Precipitation forecast for December, 2012 through February, 2013 (courtesy of the Climate Prediction Center). Above normal (A) rain was favored for much of Arkansas, especially the eastern counties.
 

As meteorological winter (December, 2012 through February, 2013) began, it appeared Arkansas was in for at/above normal precipitation. The confidence in a wet period was highest in the east. While cold snaps were expected, temperatures were supposed to finish above normal. Overall, the forecast was close.

Checking the numbers, there was more than a two inch surplus of water in parts of the east. Most reporting stations averaged 2.5 to 3.5 degrees on the warm side.

 

Average Temperatures
Site Dec, 2012 Temps +/- Jan, 2013 Temps +/- Feb, 2013 Temps +/- Overall
Fayetteville (NW AR) 42.3° +4.8° 38.5° +2.9° 38.4° -1.3° +2.1°
Harrison (NC AR) 43.8° +5.7° 39.3° +2.9° 39.5° -1.0° +2.5°
Jonesboro (NE AR) 46.1° +6.6° 41.2° +3.7° 42.1° +0.6° +3.6°
Fort Smith (WC AR) 46.2° +4.9° 43.2° +3.8° 44.6° +0.4° +3.0°
Little Rock (C AR) 48.2° +5.2° 43.7° +2.9° 44.8° +0.0° +2.7°
W Memphis (EC AR) 47.5° +6.0° 42.4° +3.6° 42.7° +0.0° +3.2°
Texarkana (SW AR) 50.8° +5.3° 46.5° +2.6° 47.7° -0.6° +2.4°
El Dorado (SC AR) 50.8° +5.3° 46.3° +2.4° 47.4° -0.4° +2.4°
Pine Bluff (SE AR) 49.4° +5.3° 45.2° +2.9° 45.6° -0.5° +2.6°

 

Precipitation
Site Dec, 2012 Pcpn +/- Jan, 2013 Pcpn +/- Feb, 2013 Pcpn +/- Overall
Fayetteville (NW AR) 2.85 -0.32 3.03 +0.16 2.82 +0.01 -0.15
Harrison (NC AR) 2.08 -1.12 3.37 +0.81 3.25 +0.61 +0.30
Jonesboro (NE AR) 3.69 -1.08 5.37 +1.94 4.42 +0.70 +1.56
Fort Smith (WC AR) 2.75 -0.54 3.97 +1.16 4.46 +1.70 +2.32
Little Rock (C AR) 5.60 +0.63 4.81 +1.26 4.75 +1.09 +2.98
W Memphis (EC AR) 3.11 -2.31 8.50 +4.32 4.99 +0.54 +2.55
Texarkana (SW AR) 4.46 -0.59 3.67 +0.27 1.78 -2.21 -2.53
El Dorado (SC AR) 6.06 +0.88 3.66 -0.64 3.00 -1.79 -1.55
Pine Bluff (SE AR) 5.19 -0.25 6.93 +3.17 4.38 +0.32 +3.24

 

Snow accumulations in the twenty four hour period ending at 600 am CST on 12/26/2012. Even though the numbers were convincingly mild, there were some chilly highlights such as a major snowstorm during the holiday season. At Little Rock (Pulaski County), nine inches of snow piled up on December 25th. There had not been accumulating snow locally on Christmas in 86 years!
In the picture: Snow accumulations in the twenty four hour period ending at 600 am CST on 12/26/2012.

 

Ice buildup was impressive at Batesville (Independence County) on 02/21/2013.
In the picture: Ice buildup was impressive at Batesville (Independence County) on 02/21/2013. The photo is courtesy of Entergy Arkansas. Click to enlarge.
 

On February 20th/21st, two to four inches of snow dusted areas from Clarksville (Johnson County) to Fort Smith (Sebastian County). That was followed by an ice storm across the northern half of the state, and quarter to three quarter inch ice accruals.

 

Severe weather was not a stranger. There were two tornadoes spawned during an event on December 19th/20th (2012), five tornadoes on January 29th (2013) and another on February 18th (2013). Most of these were weak (rated EF0/EF1).

 The WSR-88D (Doppler Weather Radar) showed some rotation nearing Sheridan (Grant County) from the southwest at 125 am CST on 12/20/2012.
In the picture: The WSR-88D (Doppler Weather Radar) showed some rotation nearing Sheridan (Grant County) from the southwest at 125 am CST on 12/20/2012. The rotation was on the northern end (or bookend) of a bowing segment (backward C-shaped line of storms). A weak tornado (rated EF1) was spawned a few miles west of town.

 

 

Twenty four hour precipitation through 600 am CST on 01/13/2013.

There was also flooding rain on January 12th/13th (2013). Three to more than five inches of rain dumped along a stalled front from Mena (Polk County) to Russellville (Pope County), Clinton (Van Buren County), Mountain View (Stone County), Hardy (Sharp County) and Pocahontas (Randolph County).
In the picture: Twenty four hour precipitation through 600 am CST on 01/13/2013.

 

Severe storms and heavy to excessive rain are still on the table heading into spring. There is still some chance for wintry precipitation, at least early in the season (March). One thing to watch is the Arctic Oscillation (AO).

The AO has to do with opposing pressure patterns over the Arctic Ocean (from 20 degrees N latitude poleward) and the mid-latitudes (where we live). Last winter, the AO was largely positive, with low pressure toward the North Pole and high pressure farther south.

 

This resulted in very few cold air intrusions into the United States. In Arkansas, Jack Frost took a break.

 When the Arctic Oscillation (AO) is in a positive phase, cold air is bottled up by strong westerlies well to the north of Arkansas.
In the picture: When the Arctic Oscillation (AO) is in a positive phase, cold air is bottled up by strong westerlies well to the north of Arkansas.

 

Link of Interest
Monitor the AO

 

More recently, the AO fluctuated more wildly, and went strongly negative at times. When this happened, it got cold. It could be argued that one of these negative turns was a contributor to the Christmas snowstorm.

Assuming the AO continues swinging sharply from positive to negative, air from Canada should plunge southward periodically and clash with warmth/moisture from the Gulf Coast. When these air masses collide, it gets active around here.

Other than the AO, forecasters closely monitor the Pacific Ocean near the equator and check water temperatures. If the water is warmer than normal for an extended period (several months), these are El Niño conditions. When the water is cool, this is La Niña. This year, neither El Niño nor La Niña is in play; that is, the water is about normal and we are in a "neutral" situation.

When the forecast for this winter was formulated, a lot of past neutral scenarios were analyzed to figure out what might happen. As mentioned, the results were admirable. 

 

The record for the most tornadoes is 107 in 1999. The upcoming severe weather season may be influenced by the Pacific. Historically in Arkansas, the most tornadoes were counted in La Niña years. There were 107 tornadoes in 1999 and 81 tornadoes in 2008. In these years, outbreaks of severe weather happened early (January) and often.
In the picture: The record for the most tornadoes is 107 in 1999. More than half of these (56) were spawned during one outbreak on January 21-22, 1999.

 

While it was not as active during neutral periods, there were memorable events that featured some of the larger and more destructive tornadoes on record. Sixteen tornadoes tore through the region on March 1, 1997. The worst of these were along Interstate 30 from Arkadelphia (Clark County) to Little Rock (Pulaski County). In all, twenty five people lost their lives.

 Sixteen tornadoes were spawned on March 1, 1997.
In the picture: Sixteen tornadoes were spawned on March 1, 1997.

 

Seven tornadoes ripped across the south and west during the evening of April 9, 2009. Six of the tornadoes were rated at least EF2, and one of these tornadoes cut across Mena (Polk County).

 

 

Precipitation forecast for March through May, 2013 (courtesy of the Climate Prediction Center).
In the picture: Precipitation forecast for March through May, 2013 (courtesy of the Climate Prediction Center). Above normal (A) rain is favored from the Great Lakes into the Ohio and Tennessee Valleys. Below (B) normal rain is expected from the Desert Southwest into the southern Plains and along the Gulf Coast.
 

From a drought standpoint, while the spring could get active, there are indications that rain may not be as prevalent in southern/western Arkansas as the season wears on. This could be part of a larger dry area to the southwest, including portions of the southern Plains and the Gulf Coast. Parts of the south had subpar precipitation in winter, including El Dorado (Union County) and Texarkana (Miller County), so this news is not good.
 

 

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