locus on forecasting

A Synoptic Analysis of the 25-26 January 1978 Blizzard Cyclone in the Central United States

Ellen M. Salmon 1 and Phillip J. Smith

Department of Geosciences, Purdue University, W. Lafayette, Ind. 47907

Abstract the blizzard except for analyses of snowfall and damage impact in Illinois included in a paper by Changnon Based on detailed surface analyses and National Meteorolog- and Changnon (1978). ical Center (NMC) facsimile products, the evolution of the The three primary objectives of the present study January 1978 midwestern blizzard-producing cyclone is described. The behavior of the storm is contrasted with the were to: 1) present a detailed analysis of the evolution actions of typical winter cyclones. Forecasts by the Limited- of the surface cyclone, 2) compare the behavior of the Area Fine Mesh (LFM) numerical model are compared with blizzard with that of typical winter cyclones, and 3) observed conditions. briefly compare predictions made by the Limited-Area An injection of polar air, resulting in the revitalization of Fine Mesh (LFM) numerical model with actual the baroclinic zone, and concurrent strong upper-air flow are found to be important factors in the dramatic intensification observed conditions. of the low. The movement and deepening of the low, although not unprecedented, were found to deviate substantially from normal winter cyclone behavior. Although LFM forecasts underestimated the deepening of the low, the amount of predicted intensification was substantial. 2. Data analysis and procedure

This study was based primarily on detailed analyses of airways surface data for the central and eastern 1. Introduction United States, spanning the period 1800 GMT 26 January-1200 GMT 26 January 1978. Particular The blizzard of 25-26 January 1978 has variously attention was given to sea level pressure, surface been categorized as the "worst blizzard in a century" temperature, 3 h pressure tendency, and 6 h liquid (Wagner, 1979) or the worst blizzard since 1918 water equivalent precipitation amounts. (Ludlum, 1978), and with good reason. The cyclone In addition, extensive use was made of the National deepened over 40 mb in 24 h, yielding numerous record Meteorological Center (NMC) facsimile map products, low sea level pressures, and was accompanied by up to including surface, 700, and 300 mb analyses and LFM 12 in of snow blown by hurricane-force winds into numerical forecasts. These maps were available from drifts as high as 25 ft (Wagner, 1979). Weather condi- 1200 GMT 24 January to 0000 GMT 27 January. tions paralyzed the midwest for several days and caused numerous accidents, injuries, and fatalities. It is evident that such a vigorous storm deserves closer scrutiny. However, the authors know of no previous studies of

3. General synoptic discussion a. Cyclone evolution 1 Present affiliation: Department of Meteorology, The Pennsylvania State University, University Park, Pa. 16802. Positions of the cyclone center, with corresponding central pressures, are shown in Fig. 1. The cyclone 0003-0007/80/050453-08$06.00 developed from a weak Gulf low that moved inland © 1980 American Meteorological Society along the southeast Texas coast at 1800 GMT 24

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January. The cyclone deepened slightly and moved slowly to the northeast through 1800 GMT 25 January, when both the rate of intensification and the speed of propagation of the cyclone increased. A central pressure drop of 9.9 mb between 0000 GMT and 0300 GMT 26 January marked the maximum rate of intensification, which occurred as the storm moved on a more northerly track from eastern Tennessee to northeastern Kentucky. Occlusion also began during this period. The minimum central pressure of 955.5 mb was reached after 1200 GMT 26 January north of Detroit, Mich. A gradual filling of the cyclone followed, and the storm returned to its slower northeastward trajectory after 1200 GMT 26 January. Precipitation was widespread in the system, with maximum amounts occurring just ahead of the low, to its east, and following the low to the west and southwest. Early in the period a northeast-southwest line north of the low (shown for 1800 GMT 25 January in Fig. 1) separated precipitation types, with snow to the west and rain to the east. By 0600 GMT 26 January, the FIG. 1. Cyclone center positions and corresponding central rain-snow line became more S-shaped (see Fig. 1), pressures (mb) for 3 h intervals from 1200 GMT 25 January corresponding to the injection of cold air south of the to 0000 GMT 26 January 1978; rain-snow dividing line low and the penetration of warm air to its north. As (dashed) for 1800 GMT 25 January and 0600 GMT 26 January. the cold air became dominant, the proportion of liquid

FIG. 2. 700 mb height contours in 30 dm intervals. Dots indicate surface cyclone positions.

Unauthenticated | Downloaded 09/26/21 02:02 AM UTC Bulletin American Meteorological Society 455 precipitation diminished until, by 1800 GMT 26 tilt of the closed center to the north and of the trough January, the precipitation was essentially all snow. to the west was apparent at this time. This tilt and the strong horizontal temperature gradient at 700 mb (not shown) are indicative of the baroclinic zone present b. Upper-air conditions from the Great Lakes to the Gulf States. The super- The upper-air flow for the period of this study is position of the two upper-air systems coincided with represented by the 700 and 300 mb patterns presented the period of greatest pressure fall within the surface in Figs. 2 and 3. Prior to cyclogenesis, a ridge over the cyclone (0000-0300 GMT 26 January). Pacific and Atlantic Oceans and a cutoff low over At 1200 GMT 26 January the dominant feature at Arizona characterized the upper-air pattern at 300 mb both 700 and 300 mb was the intensifying upper-air (not shown). A trough extended westward into northern system over the midwest, which supported the surface Manitoba from a nearly stationary closed low off the cyclone development. The closed centers at the two coasts of Labrador and Greenland. Twelve hours before levels exhibited a northeast to southwest tilt in response the beginning of the present data period, the Labrador to the southward penetration of the cold air. Finally, trough moved to the south over central Manitoba, by the last map time both upper-air lows moved north- where a closed low formed above a surface cyclone eastward to the eastern Great Lakes region with only a moving out of Canada. During the same period, the weak southward tilt remaining. Arizona low began to open and move eastward. The surface low was under areas of maximum 300 mb By 1200 GMT 25 January the trough associated flow until the last two map times, when the low moved with the Arizona low, no longer closed at 300 mb, northward away from the major baroclinic zone. began to catch up with an essentially stationary trough Recall that the cyclone began to fill during this latter extending from the low over Manitoba. At 0000 GMT period. For the first two periods the surface low was 26 January the two troughs were aligned, extending located downstream from the 300 mb trough in a southward from a closed low at 700 mb in the upper region where strong vorticity advection and correspond- midwest down to the Gulf of Mexico. A pronounced ing upper-level divergence would be expected. However,

FIG. 3. 300 mb height contours in 120 dm intervals (solid) and isotachs for wind speeds greater than 90 kt in 20 kt intervals (dashed). Dots indicate surface cyclone positions.

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FIG. 4. Surface analyses with fronts, sea level pressures in 4 mb increments (solid), and surface temperatures in 10°F intervals (dashed). by 0000 GMT 27 January the occluding surface low precipitation amounts are presented in Fig. 5. Fronts was nearly aligned with both the 700 and 300 mb were located by examining NMC frontal positions and centers. making adjustments where indicated by the more detailed surface analyses.

a. Fronts and air masses 4. Detailed surface analyses The cyclone of primary interest was centered in The blizzard-producing cyclone intensified as it merged northeastern Mississippi at 1800 GMT 25 January. with a Canadian low. This sequence of events was A stationary front extended northeast from the low accompanied by strong temperature advections and through central Kentucky and Tennessee, southeastern significant precipitation amounts, both of which are Ohio, and northwestern Pennsylvania. Cool air was dramatically revealed in detailed analyses of surface located north and west of this front, while moist air data. Sea level isobars, surface temperatures, and with intermediate temperature was positioned along fronts are depicted in Fig. 4, while isallobars and the Appalachian Mountains south of the stationary

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FIG. 5. Three hour pressure tendencies in 2 mb increments (solid) and 6 h liquid water equivalents in 0.2 in increments (dashed). Middle dots correspond to cyclone positions at map times; others represent positions 3 and 6 h before and after map times.

front and north of a warm front through the southern Alabama border moved across western Georgia. The Atlantic states. A third air mass of warm tropical air low over Wisconsin remained stationary as the asso- lay south of the warm front. The cyclone was located ciated cold front advanced south and east, spreading at the northern extent of the baroclinic zone between polar air over Illinois, Missouri, northwestern Arkansas, the cool air mass and the tropical air. and Oklahoma. The less intense Canadian low had moved into During the 0000-0600 GMT 26 January period, the northern Wisconsin with an associated cold front southeastern and midwestern cold fronts advanced extending through western Illinois, central Missouri, farther east, with much of the former moving off the and southern Kansas. The polar air behind this front Atlantic coast. The eastward-moving polar air produced was sharply colder and drier. an intensification of the baroclinic zone from the Great Over the next 6 h the primary cyclone moved Lakes to the Gulf, a feature that quite likely contributed northeastward. The stationary front and warm front to the rapid cyclone intensification previously noted for moved slightly east of their 1800 GMT positions, this period. This was associated with steep pressure while the cold front formerly on the Mississippi- gradients and marked increase in surface wind speeds,

Unauthenticated | Downloaded 09/26/21 02:02 AM UTC 458 Vol. 61, No. May 1980 especially south of the cyclone. to 0500 27 January in Table 1. Particularly significant during this period was the Both Dayton and Columbus reported lowest pressure appearance of a rare westward-moving warm front. readings at 0600 GMT 26 January, while Youngstown Between 0300 and 0600 GMT the Canadian low achieved its minimum at 0900 GMT. The delay at completely merged with the primary cyclone. Enhanced Youngstown is due to its more northern position and circulation north of the intensifying cyclone halted to the continued deepening of the low center as it the eastward progression of the cold front from Wiscon- passed through Ohio. Wind directions over Dayton sin to Indiana as the relatively warm air north and and Columbus generally backed early in the 24 h period, east of the cyclone responded to the strong easterly while Youngstown winds veered (evidence of its eastern and northeasterly flow. The resulting warm front position with respect to the low). Dayton was in the moved southwestward, bringing warmer air to Wiscon- polar air behind the low for the entire 24 h period sin, northern Illinois, and northern Indiana. (see Fig. 4) and recorded only frozen precipitation. By 1200 GMT 26 January, the polar air had pen- Columbus and Youngstown did not change to snow etrated farther into the eastern states. Although the until 0800 GMT and 1000 GMT 26 January, initial cyclone occlusion began approximately 12 h respectively. earlier, weakening of the cyclone and the characteristic Relatively strong winds associated with the sharp spiral wrapping of the fronts around the occluded low pressure gradients were maintained throughout the did not occur until the polar front became an integral period, with minimum speeds occurring closest to the part of the occlusion process. cyclone center (e.g., 0600 GMT 26 January at Colum- The effects of the passage of the storm center can be bus) and maximum speeds occurring after passage of seen by examining conditions at three stations located the low. Heaviest snow reports occurred generally 3- at about the same latitude and to the west, east, and 6 h after the passage of the low, especially at Dayton. directly in the path of the cyclone. Dayton, Columbus, This was probably due to strong convergence in the and Youngstown, Ohio, were chosen for this analysis. southwest quadrant of the low, and at Dayton may Surface winds and weather at these three stations are also have been related to the approach of the unusual shown at hourly intervals from 0600 GMT 26 January warm front.

TABLE 1. Hourly weather at stations west (Dayton), along (Columbus), and east (Youngstown) of the cyclone path. Speed is in knots; time is GMT.

Dayton Columbus Youngstown

Time Wx Dir Sp Wx Dir Sp Wx Dir Sp

(26 January) 0600 *IP —S —F 320 22G31 *R+F 350 04 R-F 100 26G34 0700 SBS 290 24G30 R-F 270 18G28 F 100 20 0800 S+BS 280 32G47 S-BSF 260 30G42 120 20G28 0900 S+BS 270 34G47 S-BSF 240 38G55 *R— 140 20G33 1000 S+BS 260 35G48 S-BS 240 40G60 R-S- -F 210 26G40 1100 S+BS 250 35G50 S-BS 240 34G49 S-F 220 30G45 1200 S+BS 250 36G43 S-BS 240 30G56 SBS 220 32G44 1300 S+BS 250 43G60 SBS 230 33G49 SBS 240 26G44 1400 fSBS 230 36G47 S-BS 240 34G55 S-BS 230 30G45 1500 SBS 230 34G47 S-BS 240 32G48 S-BS 230 27G44 1600 SBS 230 34G43 tS-BS 240 33G49 S-BS 230 32G50 1700 S-BS 230 32G43 S-BS 240 32G46 S-BS 240 28G40 1800 S-BS 230 34G44 S-BS 240 29G45 tS-BS 220 30G50 1900 S-BS 240 30G37 S-BS 240 28G40 S-BS 220 30G45 2000 S-BS 240 30G38 S-BS 240 28G40 S-BS 230 24G48 2100 S-BS 240 30G38 S-BS 240 25G35 S-BS 230 28G38 2200 S-BS 250 31G38 S-BS 230 28G38 S-BS 230 27G39 2300 S-BS 250 27G38 S-BS 230 28G38 S-BS 230 25G37 (27 January) 0000 S-BS 250 27G37 S-BS 230 25G36 S-BS 230 26G39 0100 S-BS 260 27G41 S-BS 230 27G40 S-BS 230 25G35 0200 S-BS 250 26G35 S-BS 230 24G39 S-BS 230 21G34 0300 S-BS 260 22G29 S-BS 240 25G39 S-BS 230 21G30 0400 S-BS 260 22G32 S-BS 240 28G38 S-BS 240 22G31 0500 S-BS 260 22G29 S-BS 240 25G37 S-BS 240 23G40

* Minimum pressure occurrence, f Minimum temperature in 24 h period.

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TABLE 2. Deepening and position errors of surface and 700 mb cyclone centers for 12, 24, 36, and 48 h LFM forecasts verifying at 1200 GMT 26 January 1978.

Observed sea level central pressure: 959 mb Initial Forecast Observed Deepening Location Error Forecast pressure deepening deepening error Distance Direction

48 h 1004 mb 15 mb 45 mb 30 mb 310 km 130° 36 1003 27 44 17 330 115° 24 1000 28 41 13 280 110° 12 980 13 21 8 200 90°

Observed 700 mb central height: 2520 gpm Initial Forecast Observed Deepening Location Error Forecast height deepening deepening error Distance Direction

48 h 2700 gpm —10 gpm 180 gpm 190 gpm 500 km 285° 36 2700 50 180 130 370 230° 24 2690 60 160 110 90 220° 12 2710 140 190 50 70 145°

b. Pressure changes and precipitation somewhat distorted relative to the low because of the cyclone movement during the 6 h precipitation reporting The isallobaric pattern is useful as a short-range periods. The rapid intensification of the low and indicator of pressure intensification and direction of accompanying low-level convergence throughout the propagation. Intensification is represented by nonzero cyclone region were major causes of this widespread values occurring near the pressure center, although precipitation pattern. In addition to being widespread, effects of the previous 3 h motion of the low will result precipitation was relatively heavy for a winter storm. in some distortion of the isallobar field. Propagation is A maximum 6 h liquid water equivalent of 0.96 in best seen in nonintensifying cases, in which the center was reported for Williamsport, Pa. at 1200 GMT tends to move toward the area of maximum pressure 26 January. changes. As already noted, the primary cyclone intensified markedly. This is represented in the isallobaric analyses as pressure fall maxima centered very near the cyclone center at 1800 GMT 25 January and 0000 GMT 26 5. Comparisons with typical winter cyclone behavior January, just before occlusion. In both cases the cyclone moved in a direction along an isallobaric In general, this cyclone was atypical in comparison trough. At 0600 and 1200 GMT the isallobaric low with other winter cyclones. The most notable abnormal- was displaced to the north of the cyclone center and ity was the minimum central pressure of 955.5 mb the intensification rate diminished. The cyclone (Ludlum, 1978), which approaches hurricane levels. propagated toward the low in both cases. Significant The rapid attainment of this minimum was also pressure rises occurred in the wake of the migrating unusual. Analyses by Colucci (1976) indicate an cyclone and in conjunction with the invading cold air average 3 h central pressure change of 2.5 mb for mass. deepening cyclones along the path tracked by this Two additional pressure fall regions are worthy of storm. By comparison, an average 3 h central pressure note. The first was at 0600 GMT over Illinois and decrease of 6.8 mb was observed from 1800 GMT eastern Iowa, downstream from the unusual warm 25 January through 0900 GMT 26 January. front that penetrated out of the Great Lakes. The The track of the cyclone was also atypical. As second was at 1200 GMT over southern New York determined by Reitan (1974), the primary tracks of state. It was also associated with frontal activity, and January cyclones lie well to the east or north of the path occurred as the polar front approached the preceding followed by this storm. In a study of cyclones forming occluded front. In both cases the frontal movements in the Texas-West Gulf region, Saucier (1949) found may have been enhanced by the weakening pressure the preferred track of such storms to be northeastward fields. For the latter case this movement was significant from the point of origin. Typically these storms pass because it signaled the beginning of the final occlusion south of the Appalachian Mountains and turn more process. northerly as they approach the east coast of the In a classical wave cyclone, precipitation occurs ahead United States. However, Saucier also found that the of the cold front and to the north and east of the low. small number of faster-moving cyclones track left of In the present blizzard case precipitation was observed the average path and that, at least on the first day, all around the low (Fig. 5), although the pattern is cyclones deepen most when travelling north. These

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surface forecast was greater than that of the 48 h forecast. Surface and 700 mb low observed and forecast positions are shown in Fig. 6. The surface low was consistently predicted to be east and south of the actual locations, while the closed center at 700 mb was expected to be west of the observed position in all but the 12 h forecast. The corresponding greater than observed vertical tilt in the forecast cyclone axis indicates that the forecast rate of occlusion of the system was slower than observed. The significant reduction in the tilt by 12 h suggests that the model was finally responding to the rapid intensification apparent by 0000 GMT 26 January. It is interesting to note that the 12 h forecast distance error was consider- ably less for the 700 mb closed center than for the surface low. FIG. 6. Observed and predicted positions of the surface (solid and dotted circles) and 700 mb (circumscribed Xs) centers for 12, 24, 36, and 48 h forecasts verifying at 1200 GMT 26 January.

7. Summary latter observations are consistent with the present study An analysis of the development of the blizzard-produc- and indicate that, although representing an extreme ing cyclone of 25-26 January 1978 has been presented. case, not all aspects of the present cyclone's behavior It was suggested that the reinforcement of the baroclinic were unique. zone by invading polar air flow following the super- One truly rare feature of the storm was the previously position of two upper-air troughs was primarily noted warm front extending northwest from the responsible for the rapid intensification of the storm. cyclone at 0600 GMT 26 January (see Fig. 4). This The behavior of the blizzard was found to differ warm air penetration was associated with vigorous markedly from that of normal winter cyclones, although wind speeds and the extensive closed circulation present an infrequent cyclone might exhibit similar but less throughout the troposphere. As noted by Wagner extreme tendencies. Although the LFM was conserva- (1978), surface wind gusts of 82 kt were recorded at tive, it nevertheless was successful in predicting a Cleveland and similarly strong speeds were reported significant amount of deepening for the cyclone. at many other stations. Acknowledgments. Special thanks to to Randy Peppier for drafting many of the figures and to Sharon VonTobel for 6. Comparison with LFM forecasts typing the manuscript. This study was partially supported by the Division of Atmospheric Sciences, National Science Of special interest is the extent to which NMC's Foundation, under Grants ATM 77-00932 and ATM 79-20021. primary guidance model, the LFM, was able to predict successfully this particular cyclone. Since the blizzard was near its most intense stage at 1200 GMT 26 January, comparisons have been limited to the four charts (12, 24, 36, and 48 h forecasts) valid at that References time. Particular attention was given to location and Changnon, S. A., and D. Changnon, 1978: Winter storms and intensity errors of the surface and 700 mb cyclone the recordbreaking winter in Illinois. Weatherwise, 31, centers (Table 2). 218-225. As might be expected, the largest sea level pressure Colucci, S. J., 1976: Winter cyclone frequencies over the and 700 mb height errors occurred in the 48 h forecast eastern United States and adjacent western Atlantic, and were smaller for the succeeding forecast times. All 1964-73. Bull. Am. Meteorol. Soc., 57, 548-553. errors were positive, indicating that the LFM model Ludlum, D. M., 1978: Weatherwatch: January and February was conservative in its forecast of storm intensity. 1978. Weatherwise, 31, 71-78. Despite this conservative feature, the LFM was impres- Reitan, C. H., 1974: Frequencies of cyclones and cyclogenesis for North America, 1951-1970. Mon. Wea. Rev., 102, sive in its ability to forecast significant deepening, 861-868. particularly in the 12 and 24 h forecasts. In both cases -1 Saucier, W. J., 1949: Texas-West Gulf cyclones. Mon. Wea. sea level pressure decreases in excess of 1 mb h were Rev., 77, 219-231. predicted, while at 700 mb height falls of just over 11 Wagner, A. J., 1978: Weather and circulation of January -1 and 2.5 gpm h , respectively, were forecast. 1978. Mon. Wea. Rev., 106, 581-585. The position errors were also greater for the earlier , 1979: The circulation and weather of 1978. Weatherwise, forecasts, although the distance error in the 36 h 32, 4-12. •

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