﻿326 
  0. 
  L. 
  Fassig 
  — 
  March 
  Weather 
  in 
  the 
  United 
  States. 
  

  

  This 
  division 
  into 
  high 
  and 
  low 
  areas 
  has 
  been 
  nniformly 
  main- 
  

   tained 
  for 
  convenience. 
  These 
  limits 
  were 
  adopted 
  as 
  the 
  

   mean 
  atmospheric 
  pressure 
  at 
  sea 
  level 
  is 
  approximately 
  30*0 
  

   inches 
  ; 
  any 
  area 
  above 
  30*1 
  inches 
  is 
  consequently 
  safely 
  

   above 
  normal, 
  while 
  any 
  area 
  below 
  29*9 
  inches 
  is 
  safely 
  below 
  

   normal. 
  

  

  The 
  characteristic 
  features 
  of 
  pressure 
  distribution 
  during 
  

   March 
  in 
  the 
  northern 
  hemisjDhere 
  are 
  as 
  follows: 
  a 
  large 
  area 
  

   of 
  excessively 
  high 
  pressure 
  (see 
  Plate 
  YI) 
  prevails 
  over 
  

   Asia. 
  In 
  the 
  western 
  hemisphere 
  there 
  are 
  three 
  well-deiined 
  

   areas 
  of 
  high 
  pressure 
  : 
  one 
  over 
  British 
  North 
  America, 
  

   another 
  extending 
  across 
  the 
  North 
  Atlantic 
  at 
  about 
  the 
  lati- 
  

   tude 
  of 
  thirty 
  degrees, 
  from 
  the 
  Azores 
  westward, 
  the 
  third 
  in 
  

   the 
  Pacific 
  Ocean 
  between 
  California 
  and 
  the 
  Hawaiian 
  

   Islands. 
  This 
  triple 
  arrangement 
  of 
  the 
  areas 
  of 
  high 
  pressure 
  

   about 
  the 
  United 
  States 
  during 
  March 
  plays 
  a 
  most 
  important 
  

   j)art 
  in 
  determining 
  the 
  character 
  of 
  the 
  weather. 
  The 
  areas 
  

   of 
  low 
  pressure 
  in 
  the 
  extreme 
  northern 
  portion 
  of 
  the 
  Atlantic 
  

   and 
  Pacific 
  Oceans 
  are 
  well 
  developed 
  and 
  clearly 
  defined. 
  

  

  March 
  is 
  proverbially 
  a 
  windy 
  month, 
  with 
  strong 
  contrasts 
  

   and 
  rapid 
  changes 
  in 
  temperature. 
  It 
  is 
  a 
  transitional 
  month, 
  

   during 
  which 
  there 
  is 
  a 
  breaking 
  up 
  of 
  winter 
  conditions 
  and 
  

   a 
  beginning 
  of 
  summer 
  conditions. 
  The 
  Middle 
  Atlantic 
  

   States 
  (see 
  Plate 
  YI) 
  lie 
  between 
  the 
  normal 
  March 
  iso- 
  

   therms 
  of 
  25° 
  and 
  45°, 
  though 
  the 
  mean 
  temperature 
  varies 
  

   greatly 
  from 
  year 
  to 
  year. 
  At 
  Baltimore, 
  where 
  the 
  normal 
  

   March 
  temperature 
  is 
  42°, 
  the 
  values 
  have 
  varied 
  from 
  35° 
  to 
  

   49° 
  during 
  the 
  past 
  thirty 
  years. 
  The 
  rainfall 
  east 
  of 
  the 
  

   Rocky 
  Mountains 
  attains 
  a 
  maximum 
  of 
  from 
  five 
  inches 
  to 
  

   seven 
  inches 
  in 
  the 
  eastern 
  Gulf 
  States 
  and 
  diminishes 
  steadily 
  

   to 
  the 
  west 
  and 
  north 
  to 
  about 
  one 
  inch 
  over 
  the 
  Pocky 
  

   Mountain 
  plateau. 
  Storms 
  are 
  frequent, 
  and 
  their 
  paths 
  across 
  

   the 
  country 
  evenly 
  distributed 
  from 
  the 
  Lake 
  region 
  to 
  the 
  

   Gulf 
  (see 
  fig. 
  1, 
  p. 
  335). 
  

  

  March, 
  1898.— 
  See 
  Plate 
  YII. 
  The 
  month 
  of 
  March, 
  

   1898, 
  was 
  excessively 
  warm 
  in 
  Maryland 
  and 
  Delaware 
  ; 
  at 
  

   Baltimore 
  the 
  daily 
  excess 
  of 
  temperature 
  was 
  over 
  seven 
  

   degrees. 
  There 
  was 
  but 
  one 
  short 
  period 
  of 
  frost 
  and 
  this 
  

   was 
  free 
  from 
  injurious 
  effects 
  upon 
  crops 
  in 
  these 
  States. 
  

   There 
  were 
  but 
  few 
  high 
  winds 
  and 
  none 
  of 
  them 
  destruc- 
  

   tive. 
  The 
  month 
  was 
  balmy 
  and 
  almost 
  devoid 
  of 
  the 
  usual 
  

   stormy 
  March 
  winds. 
  The 
  rainfall, 
  while 
  somewhat 
  below 
  

   the 
  normal, 
  was 
  sufficient 
  to 
  supply 
  all 
  the 
  needs 
  of 
  growing 
  

   crops. 
  Crop 
  correspondents 
  of 
  the 
  United 
  States 
  Weather 
  

   Bureau 
  in 
  Maryland 
  and 
  Delaware 
  reported 
  vegetation 
  at 
  the 
  

   close 
  of 
  the 
  month 
  from 
  three 
  to 
  four 
  weeks 
  in 
  advance 
  of 
  the 
  

   average 
  season. 
  

  

  